WO2011008168A1

WO2011008168A1 - Organic light emitting materials

Info

Publication number: WO2011008168A1
Application number: PCT/SG2009/000250
Authority: WO
Inventors: Zhikuan Chen; Ying Lin; Qinde Liu; Zhun Ma
Original assignee: Agency For Science, Technology And Research
Priority date: 2009-07-14
Filing date: 2009-07-14
Publication date: 2011-01-20
Also published as: TW201127935A

Abstract

The present invention provides a blue light emitting compound having (1) a backbone portion, which backbone portion includes a hole transporting portion comprising a triarylamine group; (2) a side chain portion attached to the backbone portion, which side chain portion includes an electron transporting portion comprising an electron deficient aryl group; and (3) a spacer portion located between the hole transporting portion and the electron transporting portion.

Description

ORGANIC LIGHT EMITTING MATERIALS

FIELD OF THE INVENTION

The present invention relates generally to light emitting organic materials, particularly electroluminescent organic materials, and to light emitting devices containing such compounds. BACKGROUND

Certain organic materials, including organic polymers, are able to conduct charge due to inclusion of an extensive system of pi bonds in the molecule. That is, compounds with connected or conjugated pi systems, such as polyarylene compounds or

polyarylenevinylene compounds (e.g. poly(phenylenevinylene) and polyfluorene), have a set of pi molecular orbitals that overlap and extend along the molecule. These extended pi molecular orbitals, when unfilled or when only partially filled with electrons, provide "channels" for transport of additional electrons along the molecule when a voltage is applied to the molecule. Several such extended pi orbitals can form across a conductive organic material, each having different structure and energy levels. The molecular orbital having the lowest energy level is often an effective path for transport of electrons supplied from an electrode.

In order for these materials, and polymers in particular, to luminesce as an electron is being transported across the molecule, one or more electrons must move from a filled or partially filled higher energy orbital to an unfilled or partially filled lower energy orbital. If the energy released by the electron as it passes from a high energy state to a low energy state is in the visible spectrum, these molecules will emit light. Briefly, when a hole is injected into a conductive organic molecule, the molecule becomes positively charged, and conversely when an electron is injected into such a molecule, it becomes negatively charged. A charged molecule can obtain an opposite charge from an adjacent molecule, resulting in charge transport in a composition containing the conductive organic molecule. An injected electron and hole can recombine within the emissive layer, forming a bound electron/hole pair, termed an exciton, which can emit energy when it relaxes from an excited state to a lower energy state. Depending on the wavelength of the emitted energy, the energy may be released as ultraviolet or visible light.

Electroluminescent organic materials can be conjugated polymers or organic molecules. Examples of polymeric electroluminescent organic materials include poly(1 ,4- phenylenevinylene)s, polyfluorenes, and their derivatives. Electroluminescent polymers are attractive because of their solution processability, which is a relatively cost effective method for manufacturing electronic devices containing electroluminescent organic materials.

Non-polymeric molecules represent another category of light emitting materials, for example as emitters or as charge transporting materials.

Both polymeric and non-polymeric materials have been used in organic light emitting devices, such as organic light emitting diodes (OLEDs).

However, many of the current organic light emitting materials typically have imbalanced charge transporting characteristics. Generally, light emitting materials are able to conduct only one charge carrier, either holes or electrons, but typically not both. For example, poly(1 ,4-phenylenevinylene)s or alkoxy-substituted poly(1 ,4-phenylenevinylene)s are good hole transporters, whereas tris-(8-hydroxyquinoline) aluminum (III) (Alq3) is an electron transporter. Imbalanced charge transporting in OLED devices results in low device efficiency. To address this issue, multilayer devices with one or more of a hole injection layer, hole transport layer, electron injection layer and electron transport layer have been explored. A typical construction includes a hole transport layer, an emissive layer and an electron transport layer, with possible inclusion of a hole injecting layer and/or electron injecting layer. This approach can improve device efficiency but results in increased complexity and cost.

Another approach to this problem is to tune the charge transporting property of the materials by incorporation of either hole transporting portions, or electron transporting portions or both into the material to try to improve the device performance. Although some materials comprising one or both of hole transporting and electron transporting portions have been developed, and the performance may be better than materials containing only one component, to date the reported device performance based on such materials is still not satisfactory.

As one of the key components for OLEDs, blue light emitting materials, which can be applied in full colour displays or solid state lighting, are the most challenging topic in OLED research because of their relative low device efficiency and short lifetime, compared to green or red light emitting materials.

In particular, poly(1 ,4-phenylene)s and polyfluorenes and their respective derivatives have been widely investigated and have demonstrated promising device performance for blue OLED application. However, low luminescent efficiency and short device lifetime are the main issues for these blue light emitting materials. For fluorene based materials, the present inventors have found that low device efficiency is mainly caused by an imbalanced charge transporting character. Poor charge injection is also a significant factor.

The present inventors have found that a further technical issue to be addressed in the design of suitable materials is the inter- or intra-molecular interaction between the hole transporting portions and electron transporting portions, which can lead to

electroluminescent spectrum red shift and lower device efficiency. Accordingly, the present inventors note that this issue also need be addressed to achieve high efficiency and colour stability for blue light emission.

The present inventors have also noted that aggregation of the material can occur, which causes red shift of the emissive spectra. In particular, most blue light emitting materials are fluorene-based polymers or small molecules and fluorene-based polymers/oligomers in particular are prone to form aggregates. The undesirable red shift of the emissive spectra leads to poor colour stability and a lowering of the device efficiency.

Thus, there exists a need for new materials that can be used in an organic light emitting layer in an electroluminescent device and in particular for new blue light emitting materials.

SUMMARY OF THE INVENTION The present invention provides luminescent compounds and materials, methods for their preparation, and their use in light emitting devices, including electroluminescent diodes. At its most general, the present invention proposes that a luminescent material having a conjugated backbone is composed of an electron donating triarylamine group in the backbone and an electron withdrawing group in a pendant side chain with a spacer portion separating the two groups. In one aspect, the present invention provides a compound having (1 ) a backbone portion, which backbone portion includes a hole transporting portion comprising a triarylamine group; (2) a side chain portion attached to the backbone portion, which side chain portion includes an electron transporting portion comprising an electron deficient aryl group; and (3) a spacer portion located between the hole transporting portion and the electron transporting portion.

In a further aspect, the present invention provides a compound comprising the structure according to formula I f A- B - C^

I ⁿ

D

(l)

wherein:

-A- or -A-B- comprises a triarylamine and is optionally substituted;

each of -B- and -C- independently comprises an arylene and is optionally substituted;

-D is an electron deficient aryl, aryl vinylene or aryl ethynylene, and is optionally substituted with an electron withdrawing group; and

n is independently 1 to 200.

In a further aspect, the present invention provides a compound comprising the structure according to formula II:

(H) wherein:

each of Ar₁, Ar₂, Ar_4a, Ar_4bl Ar₅, Ar_7a and Ar_7b is independently arylene, and is optionally substituted;

Ar₃ is independently aryl, aryl vinylene or aryl ethynylene, and is optionally substituted;

Ar₆ is independently an electron deficient aryl, aryl vinylene or aryl ethynylene, optionally substituted with an electron withdrawing group, and is optionally further substituted;

X is independently alkylene, alkenylene, -O-, -OC(O)-, -C(O)O-, -C(0)NR_A-, or - NR_AC(0)-, wherein each R_A, if present, is independently H, alkyl or aryl and is optionally substituted;

e is independently 0 or 1 ;

each of m, s, v and w is independently 1 to 20;

each of I, p, r and t is independently 0 to 20;

z is independently 0 to 3; and

n is independently 1 to 200;

and wherein:

at least one of p and r≠ 0

and wherein:

when n≠ 1 at least one of I and t≠ 0. In a further aspect, the present invention provides a compound according to formula (III):

(III) wherein

An, Ar₂, Ar₃, Ar₄₃, Ar_4b, Ar₅, Ar₆, Ar_7a, Ar_7b and X are as defined above; and e, I, m, p, r, s, t, v, w, z and n are as defined above;

and wherein

each Of Ar₈ and Ar₉ is independently aryl, aryl vinylene or aryl ethynylene and is optionally substituted.

In a further aspect, the present invention provides a light emitting device comprising a compound as described herein.

In another aspect, the present invention provides an organic electroluminescent device comprising a compound as described herein.

In a related aspect, the present invention provides an organic light emitting diode (OLED) comprising a compound as described herein. In another aspect, there is provided a thin film comprising a compound as described herein.

In a further aspect, there is provided a device comprising an anode, a cathode and a thin film as described herein, the thin film being disposed between the anode and the cathode.

In a further aspect, there is provided a device comprising: an anode; an emissive layer disposed on the anode, the emissive layer comprising a compound as described herein; and a cathode disposed on the emissive layer. In another aspect, the present invention provides a device comprising an emissive layer, wherein the emissive layer comprises a compound or thin film as described herein. In another aspect, there is provided a device comprising: an anode; a hole transporting layer disposed on the anode; an emissive layer disposed on the hole transporting layer; an electron transporting layer disposed on the emissive layer; and a cathode disposed on the electron transporting layer; wherein at least one of the hole transporting layer, the emissive layer and the electron transporting layer comprises a compound or thin film as described herein.

In still another aspect, there is provided a device comprising: an anode; a hole injecting layer disposed on the anode; a hole transporting layer disposed on the hole injecting layer; an emissive layer disposed on the hole transporting layer; an electron transporting layer disposed on the emissive layer; and a hole blocking layer disposed on the electron transporting layer; an electron injecting layer disposed on the emissive layer; a cathode disposed on the electron injecting layer; wherein at least one of the hole transporting layer, the emissive layer or the electron transporting layer comprises a compound or thin film as described herein.

In a further aspect, the present invention provides a photovoltaic cell comprising an active layer wherein the active layer comprises a compound or thin film as described herein.

In a further aspect, the present invention provides a chemical or bio sensor comprising a sensing layer wherein the sensing layer comprises a compound or thin film as described herein. Suitably the devices referred to herein are display devices, for example a display panel.

Accordingly, a further aspect of the present invention provides a display device comprising a compound or thin film as described herein. In a further aspect, the present invention provides a method of making a compound as described herein.

In a further aspect, the present invention provides a method of making a device (e.g. an OLED or a display device) as described herein. In a further aspect, the present invention provides a use of a compound as described herein in a device (e.g. an OLED or a display device) as described herein.

Other aspects and features of the present invention will become apparent to those of ordinary skill in the art upon review of the following description of the invention including the examples, as read in conjunction with the accompanying figures.

Any one of the aspects may be combined with any one or more of the other aspects, optinal and preferred features associated with one aspect suitably apply to any one of the other aspects. In particular, features described with reference to a method or use suitably also apply to a product (compound, device, etc) and vice versa.

DETAILED DESCRIPTION OF THE INVENTION Embodiments of compounds described herein are electroluminescent, meaning that these compounds emit light when an electrical current is passed through them. Thus, these compounds are adapted for use in a charge transport layer or a light emitting layer in an organic electronic device. Conveniently, the compounds as described herein are composed of a hole transporting portion in the backbone, an electron transporting portion in a side chain (e.g. comprising a pendant electron deficient group) and a spacer portion located between the hole and electron transporting portions. This combination of structural features not only provide the compounds with ambipolar transporting functionality but also achieve good device performance. In particular, as described and illustrated herein, device efficiency, emissive red shift, device lifetime and driving voltage can be favourably altered (e.g. reduced or eliminated as appropriate) by adopting the particular arrangement of components described herein. As well, suitably these compounds are solution processable, and may be readily purified to a relatively high extent. Thus, embodiments address the problems described above and provide a compound that performs well in OLEDs for example.

Thus, in one aspect, the present invention provides a compound having (1 ) a backbone portion, which backbone portion includes a hole transporting portion comprising a triarylamine group; (2) a side chain portion attached to the backbone portion, which side chain portion includes an electron transporting portion comprising an electron deficient aryl group; and (3) a spacer portion located between the hole transporting portion and the electron transporting portion.

The light emitting compounds described herein are composed of monomer units or portions with different functionalities. Among them, a first type of monomer is based on triarylamine, which can help holes to be injected from the anode and transported in the emissive layer. A second type of monomer unit is composed of a pendant electron deficient structure, which can help to transport electrons in the emissive layer. The hole transporting monomer unit and electron transporting monomer unit are separated from each other by a third monomer unit to reduce or prevent intramolecular interaction between the first and second monomer units. This intramolecular interaction has been found by the present inventors to be undesirable because it can lead to emissive spectrum red shift. Thus, by providing the different monomer units in the arrangement specified herein, both holes and electrons can be injected into the emissive layer and transported in the emissive layer.

In particular, by providing an electron deficient group as a side chain or pendant group (i.e. not part of the backbone) the present inventors have achieved a significant improvement in the problem of emissive spectrum red-shift. Specifically, the present inventors have found that placement of the electron deficient group in this way, in combination with the triarylamine portion in the backbone, significantly reduces or prevents functional interaction between the hole transporting and electron transporting portions. In this way the problem of interaction via conjugation is ameliorated.

In embodiments, the structures of both the hole transporting monomers and electron transporting monomers are bulky enough to assist in reducing or preventing

intermolecular interaction between the two types of monomer unit. Accordingly, the design of the materials described herein suitably enhances the colour stability of light emitting materials, particularly for blue light emission applications and especially for fluorine-based light emitting materials.

The luminescent compounds as described herein can be used in the emissive layer of a light emitting device, or as dopant in a suitable layer in such a device. A further use is as a host material for electroluminescent light emitting diodes. The compounds defined herein can be fabricated into LED devices, for example through a solution process.

Suitably the compounds emit blue, green, red or white light.

Preferably the compound is a blue-light-emitting compound. Suitably the compound emits light at a wavelength in the range 400nm to 600nm. Suitably the emission maximum is at less than 490nm, preferably less than 480nm and most preferably less than 470nm. In other embodiments, the compound is a green-light-emitting compound. In other embodiments, the compound is a red-light-emitting compound.

In other embodiments, the compound is a white-light-emitting compound.

Adjustment of the emissive portions of the compound can be used to achieve a change in emission wavelength, for example any one or more of the following groups: Ar₁, Ar₂, Ar₄₃, Ar_4b or Ar_7b. The backbone can be conjugated or non-conjugated. Suitably the backbone is conjugated.

Suitably the compound has the structure according to formula I: f A- B - C^

D

(l)

wherein:

-A- or -A-B- comprises a triarylamine and is optionally substituted;

n is independently 1 to 200. Thus the triarylamine is incorporated into the backbone of the compound through bonding of two of the three amino aryl groups, i.e. the triarylamine is bidentate. Suitably -A- or -A- B- has the structure -Ar-N(Ar)-Ar-, wherein each Ar is independently as described herein. In this arrangement, -B-, whether or not it is part of the triarylamine, is a spacer between the hole transporting (triarylamine containing) portion and the electron transporting portion provided by the backbone arylene -C- and electron deficient group -D.

Preferably the compound comprises the structure according to formula II:

(H) wherein:

each Of Ar₁, Ar₂, Ar_4a, Ar₅, Ar_7a and Ar_7b is independently arylene, and is optionally substituted;

Ar_4b is independently arylene, alkylene, bidentate ether, bidentate ester or bidentate amide and is optionally substituted;

X is independently alkylene, alkenylene, -O-, -OC(O)-, -C(O)O-, -C(O)NR_A-, or - NR_AC(O)-, wherein each R_A, if present, is independently H, alkyl or aryl and is optionally substituted;

e is independently O or 1 ;

each of m, s, v and w is independently 1 to 20;

each of I, p, r and t is independently 0 to 20;

z is independently 0 to 3; and n is independently 1 to 200;

and wherein:

at least one of p and r≠ 0

and wherein:

when n≠ 1 at least one of I and t≠ 0.

Thus, in such compounds, the hole transporting function is provided by the portion:

in the case of e = 1 , and

or

in the case of e = 0. The electron transporting function is provided by:

The hole transporting and electron transporting functional units are separated by one or more of the spacer groups:

The compound can have any suitable terminal or end-cap groups. However, aryl, aryl vinylene and aryl ethynylene groups are preferred.

Thus, suitably the compound comprises the structure according to formula III:

(III)

wherein

Ar₁, Ar₂, Ar₃, Ar_4a, Ar_4b, Ar₅, Ar₆, Ar_7a, Ar_7b and X are as defined above; and e, I, m, p, r, s, t, v, w, z and n are as defined above;

and wherein

each of Ar₈ and Ar₉ is independently aryl, aryl vinylene or aryl ethynylene and is optionally substituted. As shown schematically in Figure 1 , a compound 10 as described herein, which can be an oligomer or polymer, incorporates a triarylamine portion 12 that provides a hole transporting function. As well, the compound 10 has an electron transporting portion 14, comprising the group - Ar₅(Ar₆)- wherein Ar₆ is electron deficient and is optionally substituted by one or more electron withdrawing groups.

In addition, the compound 10 includes spacer portions 16, 18, 20 and 22. Not all of these need to be present in the compound (i.e. not all of I, p, r and t must≠ 0), provided that there is at least one spacer portion between the hole transporting portion 12 and the electron transporting portion 14. Typically one or both of spacer portions 16 and 18 will be present. These spacer groups reduce or prevent intramolecular interaction between the hole transporting portion 12 and electron transporting portion 14.

In embodiments where n = 1 , there may be no requirement for spacer portions 20 and 22 because there is no repeating unit whereby the hole transporting and electron transporting portions alternate along the molecule and therefore no requirement to distance the electron transporting portion 14 from a neighbouring hole transporting portion 12.

Nevertheless, aryl groups 20 and/or 22 may be present, for example to tune the emission or performance characteristics of the compound.

Indeed, any adjustment of the conjugated building blocks in the backbone can suitably be used to affect the emission wavelength.

Figure 2 illustrates the backbone portion 24 of the compound.

Suitably each of Ar₁, Ar₂, Ar₄₃, Ar_4b, Ar₅, Ar₇₃ and Ar_7b is independently C_5-1Ooarylene, preferably C_5-8oarylene, more preferably C_5-50arylene, more preferably C_5-40arylene, most preferably C_5-30arylene, and is optionally substituted.

Suitably each of Ar₁, Ar₂, Ar_4a, Ar_4b, Ar₅, Ar₇₃ and Ar_7b is independently at least C₆arylene (e.g. C_6-50arylene). Thus, suitably each Of Ar₁, Ar₂, Ar_4a, Ar_4b, Ar₅, Ar_7a and Ar_7b is independently C_6-iooarylene, preferably C_6-80arylene, more preferably C₆-₅₀arylene, more preferably C_6-4Oarylene, and most preferably C₆-₃oarylene, and is optionally substituted Suitably, each of An, Ar₂, Ar_4a, Ar_4b, Ar₅, Ar₇₃ and Ar_7b is independently carboarylene or heteroarylene. Preferably each Of Ar₁, Ar₂, Ar₄₃, Ar_4b, Ar₅, Ar_7a and Ar_7b is independently carboarylene.

Suitably, if any one or more Of Ar₁, Ar₂, Ar₄₃, Ar_4b, Ar₅, Ar₇₃ and Ar_7b is heteroarylene, the heteroarylene contains one or more heteroatoms selected from O, S, N, Si and P, preferably one or more selected from O, S and N, more preferably one or more selected from O and N, and most preferably N.

Suitably, if any one or more Of Ar₁, Ar₂, Ar₄₃, Ar_4b, Ar₅, Ar₇₃ and Ar_7b is heteroarylene, the heteroarylene contains one, two, three or four heteroatoms. Where a plurality of heteroatoms are present, they may be the same or different.

Suitably, each Ar₁ is independently C_5-1Ooarylene, preferably C_5-50arylene, more preferably C_5-3oarylene, more preferably C_5-15arylene, and most preferably C₆arylene, and is optionally substituted.

Suitably, each Ar₁ is independently carboarylene or heteroarylene. Preferably Ar₁ is carboarylene.

Preferably each Ar₁ is independently phenylene, fluorenylene, carbazolylene, diarylamino, spirobifluorenylene, spirosilabifluorenylene, indenocarbazolylene, indenofluorenylene, thienylene, thienothienylene or benzothiadiazolylene and is optionally substituted. In this way, if two or more Ar₁ are present, a combination of the above building blocks may be present.

Preferably each Ar₁ is independently phenylene and is optionally substituted. Preferably Ar₁ is unsubstituted. Suitably, if Ar₂ is present (i.e. if e=1 ) then Ar₁ and Ar₂ are the same. However, in other embodiments Ar₁ and Ar₂ are different.

Suitably, each Ar₂ is independently C_5-1o_Oarylene, preferably C_5-80 arylene, more preferably C₅.₅oarylene, more preferably C_5-30arylene, more preferably C_5-15arylene, and most preferably C₆arylene, and is optionally substituted. Suitably, each Ar₂ is independently carboarylene or heteroarylene. Preferably Ar₂ is carboarylene.

Preferably each Ar₂ is independently phenylene, fluorenylene, carbazolylene, diarylamino, spirobifluorenylene, spirosilabifluorenylene, indenocarbazolylene, indenofluorenylene, thienylene, thienothienylene or benzothiadiazolylene and is optionally substituted. In this way, if two or more Ar₂ are present, a combination of the above building blocks may be present.

Preferably each Ar₂ is independently phenylene and is optionally substituted. Preferably Ar₂ is unsubstituted.

Suitably, Ar₂ and Ar₁ are the same. However, in other embodiments Ar₂ and Aη are different.

Suitably, each Ar₄₃ is independently C_5-1ooarylene, preferably C_5-50arylene, more preferably C_5-30arylene, and most preferably C_5-15arylene, and is optionally substituted. Suitably, each Ar₄₃ is independently carboarylene or heteroarylene. Preferably Ar₄₃ is carboarylene.

Preferably each Ar₄₃ is independently phenylene, fluorenylene, carbazolylene,

diarylamino, spirobifluorenylene, spirosilabifluorenylene, indenocarbazolylene, indenofluorenylene, thienylene, thienothienylene or benzothiadiazolylene and is optionally substituted. In this way, if two or more Ar₄₃ are present, a combination of the above building blocks may be present.

Preferably each Ar₄₃ is independently fluorenylene and is optionally substituted, suitably as follows:

Typically each Ar₄₃ is independently substituted fluorenylene, preferably substituted at the 9-position, suitably as follows:

Preferably each Ar₄₃ is independently substituted fluorenylene, preferably di-substituted at the 9-position, suitably as follows:

A particularly preferred substituent is alkyl, preferably C_2-i₅alkyl, more preferably C_2-ioalkyl, more preferably C_3-8alkyl, more preferably C_5-7alkyl and most preferably C₆alkyl, and the alkyl substituent is optionally substituted.

In particularly preferred embodiments, each Ar₄₃ is independently

Suitably, each Ar_4b is independently C_5-1ooarylene, preferably C_5-50arylene, more preferably C_5-3₀arylene, and most preferably C_5-i₅arylene, and is optionally substituted.

Suitably, each Ar_4b is independently carboarylene or heteroarylene. Preferably Ar_4b is carboarylene.

Preferably each Ar_4b is independently phenylene, fluorenylene, carbazolylene,

diarylamino, spirobifluorenylene, spirosilabifluorenylene, indenocarbazolylene or indenofluorenylene, and is optionally substituted.

Preferably each Ar_4b is independently fluorenylene and is optionally substituted.

In embodiments, Ar_4b is the same as Ar_4a. Alternatively or additionally, Ar_4b can be the same as Ar_7a.

*****

Suitably, each Ar₅ is independently C_5-ioQarylene, preferably C_5-5oarylene, more preferably C_5-3oarylene, and most preferably C_5-15arylene, and is optionally substituted. Suitably, each Ar₅ is independently carboarylene or heteroarylene. Preferably Ar₅ is carboarylene.

Preferably each Ar₅ is independently phenylene, fluorenylene, carbazolylene, diarylamino, spirobifluorenylene, spirosilabifluorenylene, indenocarbazolylene, indenofluorenylene, thienylene, thienothienylene or benzothiadiazolylene and is optionally substituted. In this way, if two or more Ar₅ are present, a combination of the above building blocks may be present.

Preferably each Ar₅ is independently fluorenylene and is optionally substituted.

Suitably each Ar₅ is bonded to Ar₆ at the 9-position, as follows:

Preferably each Ar₅ is spiro bonded to Ar₆. In the preferred arrangement wherein Ar₆ is optionally substituted fluorenyl, suitably Ar₅(Ar₆) is as follows:

Suitably, each Ar_7a is independently C_5-1Ooarylene, preferably C₅.₅₀arylene, more preferably C_5-30arylene, and most preferably C_5-15arylene, and is optionally substituted. Suitably, each Ar_7a is independently carboarylene or heteroarylene. Preferably Ar_7a is carboarylene.

Preferably each Ar_7a is independently phenylene, fluorenylene, carbazolylene,

diarylamino, spirobifluorenylene, spirosilabifluorenylene, indenocarbazolylene, indenofluorenylene, thienylene, thienothienylene or benzothiadiazolylene and is optionally substituted. In this way, if two or more Ar_7a are present, a combination of the above building blocks may be present.

Preferably each Ar_7a is independently fluorenylene and is optionally substituted, suitably as follows:

Typically each Ar_7a is independently substituted fluorenylene, preferably substituted at the 9-position, suitably as follows:

Preferably each Ar_7a is independently substituted fluorenylene, preferably di-substituted at the 9-position, suitably as follows:

A particularly preferred substituent is alkyl, preferably C_2-i₅alkyl, more preferably C_2-ioalkyl, more preferably C_3-δalkyl, more preferably C_5-7alkyl and most preferably C₆alkyl, and the alkyl substituent is optionally substituted.

In particularly preferred embodiments, each Ar_7a is independently

Suitably, each Ar_7b is independently C_5-i_Ooarylene, preferably C_5-50arylene, more preferably C_5-30arylene, and most preferably C_5-15arylene, and is optionally substituted.

Suitably, each Ar_7b is independently carboarylene or heteroarylene. Preferably Ar_7a is carboarylene.

Preferably each Ar_7b is independently phenylene, fluorenylene, carbazolylene,

Preferably each Ar_7b is independently fluorenylene and is optionally substituted. *^****

Where two or more spacer groups are present, they may be the same or different.

Thus, in embodiments Ar_4a, Ar_4b, Ar_7aand Ar_7b are the same. In other embodiments some or all of Ar_4a, Ar_4b, Ar_7a and Ar_7b are different. In embodiments Ar₄₃ and Ar_7aare the same. In embodiments Ar_4b and Ar_7bare the same. In embodiments Ar₄₃ and Ar_4bare the same. In embodiments Ar_7a and Ar_7bare the same. Each of Ar_4a, Ar_4b, Ar_7a and Ar_7b can be conjugated or non-conjugated with the groups to which it is attached. Preferably each Of Ar₄₃, Ar_4b, Ar_7aand Ar_7b is independently conjugated with the groups to which it is attached. Thus, it is preferred that each of the spacer groups Ar₄₃, Ar_4b, Ar₇₃ and Ar_7b provides a conjugated link between neighbouring groups. In particular, it is preferred that each Of Ar₄₃, Ar_4b, Ar₇₃ and Ar_7b is independently conjugated with the hole transporting portion (-Ar₁-N(Ar₃J-Ar₂-) and/or Ar₅.

Suitably Ar₄₃, Ar_4b, Ar_7a and Ar_7b are "neutral" in the sense that they are neither electron deficient nor electron rich. That is, suitably Ar_4a, Ar_4b, Ar_7aand Ar_7b do not provide a hole transporting or electron transporting function.

Suitably, each Ar₃ is independently C_5-i₀₀aryl, C_5-1Ooaryl vinylene or C_5-1Ooaryl ethynylene, preferably C_5-50aryl, C_5-5oaryl vinylene or C_5-50aryl ethynylene, more preferably C_5-3oaryl, C_5- ₃oaryl vinylene or C_5-3oaryl ethynylene, and most preferably C_5-15aryl, C_5-15aryl vinylene or Cs-i₅aryl ethynylene, and is optionally substituted.

Preferably each Ar₃ is independently phenylene, fluorenylene, carbazolylene, diarylamino, spirobifluorenylene, spirosilabifluorenylene, indenocarbazolylene, indenofluorenylene, thienylene, thienothienylene or benzothiadiazolylene and is optionally substituted. In this way, if two or more Ar₃ are present, a combination of the above building blocks may be present.

Preferably each Ar₃ is independently phenyl and is optionally substituted.

In particularly preferred compounds, each Ar₃ is independently carbazoyl-substituted phenyl and is optionally substituted, suitably as follows:

In embodiments, the carbazoyl group is substituted at one or both of the 3- and 6- positions, suitably as follows:

Preferably the substituent at one or both of the'3- and 6-positions is carbazoyl, suitably as follows:

Preferably each Ar₆ is independently electron deficient C_5-1Ooaryl, C_5-i_Ooaryl vinylene or C_5- iooaryl ethynylene, more preferably C_5-50aryl, C_5-50aryl vinylene or C_5-50aryl ethynylene, more preferably C_5-3oaryl, C_5-3oaryl vinylene or C_5-30aryl ethynylene, and most preferably C_5-i₅aryl, C_5-15aryl vinylene or C_5-i₅aryl ethynylene, and is optionally substituted with an electron withdrawing group, and is optionally further substituted. The electron deficient nature of Ar₆ may be achieved by selection of an electron deficient group per se, or by providing one or more electron withdrawing substituents. Suitable electron withdrawing groups are discussed herein.

Suitably each Ar₆ is conjugatedly or non-conjugatedly connected to Ar₅. Preferably Ar₆ is conjugatedly connected to Ar₅.

In embodiments, each Ar₆ is independently one of the following structures:

in which each of R, R", R" and R¹" is independently halo (especially -F or -Cl), -CN, -NO₂, -CO, thionyl, sulphonyl, C_1-2oalkyl, C_1-2operfluoroalkyl, C_1-2oalkoxy, C_5-50aryl, C_5-50arylene vinylene, or C_5-50arylene ethynylene, and q is an integer from 0 to 6.

It will be appreciated that although certain of the aryl groups above are depicted as either monovalent or bivalent, any of groups may be either monovalent or bivalent, depending on the context in which the aryl group occurs in the compound as described herein. As well, certain of the compounds are depicted with the bond that attaches the group to the remaining portion of the compound as entering into the centre of the aryl group ring, either at an atom or across a bond. It will be appreciated that such depiction is intended to represent that the particular aryl group may be attached to the remaining portion of the compound by a bond at any available position on the ring.

Suitably each Ar₆ is independently fluorenyl subtituted with an electron withdrawing group. In particularly preferred arrangments Ar₆ is phenyl-substituted fluorenyl, wherein the phenyl is substituted with an electron withdrawing group. Suitably the fluroenyl is bonded to Ar₅ at the 9-position as follows:

Preferably the fluorenyl is substituted at one or both of the 2- and 7-positions, suitably with phenyl. For example, the following arrangement is preferred:

wherein R_EW is an electron withdrawing group. Preferably each -Ar₅(Ar₆)- is spirobifluorenylene substituted with an electron withdrawing group.

The present inventors have found that the -Ar₅(Ar₆)- unit containing the electron deficient Ar₆ group as a pendant group can enhance electron transport in the polymer.

Preferably each Ar₈, if present, is independently C_5-i_Ooaryl, C_5-i_Ooaryl vinylene or C_5-100aryl ethynylene, preferably C_5-50aryl, C_5-50aryl vinylene or C_5-5oaryl ethynylene, more preferably C5-i5ary'. C_5-15aryl vinylene or C_5-i₅aryl ethynylene, and most preferably C₆aryl, C₆aryl vinylene or C₆aryl ethynylene, and is optionally substituted.

Preferably each Ar₈ is independently phenyl and is optionally substituted.

Preferably each Ar₉, if present, is independently C_5-1Ooaryl, C_5-i_Ooaryl vinylene or C_5-1Ooaryl ethynylene, preferably C_5-50aryl, C_5-50aryl vinylene or C_5-50aryl ethynylene, more preferably C_5-3oaryl, C_5-30aryl vinylene or Cs-₃oaryl ethynylene, more preferably C_5-i₅aryl, C₅.₁₅aryl vinylene or C_5-i₅aryl ethynylene, and most preferably C₆aryl, C₆aryl vinylene or C₆aryl ethynylene, and is optionally substituted.

Preferably each Ar₉ is independently phenyl and is optionally substituted.

Preferably, R_A, if present is independently H, C_1-2oalkyl or C_5-i₅aryl and is optionally substituted.

According to formula II, each of m, s, v and w is independently 1 to 20.

Preferably each of m, s, v and w is independently 1 to 20, more preferably 1 to 10, more preferably 1 to 5, more preferably 1 to 3, and most preferably 1.

If any one of m and s is greater than one, then the relevant Ar group (for example An for m) is chosen independently for each occurrence of that Ar group. For example, where m is 3, each of the 3 Aη groups is chosen independently from the remaining 2 Ar₁ groups (and the same for Ar₂, if present, and Ar₃).

Similarly, If any one of v and w is greater than one, then the relevant groups within the bracketed portion (e.g. [(Ar_7a)_r-(Ar₅(Ar₆))_s-(Ar_7b),] in the case of w) is chosen independently for each occurrence of v or w. Thus, for example, different triarylamine hole transporting portions and/or different electron transporting portions are possible for each occurrence of m and s and/or v and w, respectively.

According to formula II, m is independently 1 to 20. Preferably each m is independently 1 to 15, more preferably 1 to 10, more preferably 1 to 5, more preferably 1 to 3, and most preferably 1.

According to formula II, s is independently 1 to 20. Preferably each s is independently 1 to 15, more preferably 1 to 10, more preferably 1 to 5, more preferably 1 to 3, and most preferably 1.

According to formula II, v is independently 1 to 20. Preferably each v is independently 1 to 15, more preferably 1 to 10, more preferably 1 to 5, more preferably 1 to 3, and most preferably 1.

According to formula II, w is independently 1 to 20. Preferably each w is independently 1 to 15, more preferably 1 to 10, more preferably 1 to 5, more preferably 1 to 3, and most preferably 1.

According to formula II, each of I, p, r and t is independently 0 to 20 but at least one of p and r≠ 0 and when n≠ 1 at least one of I and t≠ 0.

Subject to the requirement that at least one of p and r≠ 0 and when n≠ 1 at least one of I and t≠ 0, preferably each of I, p, r and t is independently 0 to 10, more preferably 0 to 5, more preferably 0 to 3, and most preferably 0 or 1. Preferably I = 1 and r = 1.

Suitably p = 0 and t = 0.

If any one of I, p, r and t is greater than one, then the relevant Ar group (for example Ar₄₃ for I) is chosen independently for each occurrence of that Ar group. For example, where I is 3, each of the 3 Ar₄₃ groups is chosen independently from the remaining 2 Ar₄₃ groups. *****

Subject to the requirement that when n≠ 1 at least one of I and t≠ O₁ preferably each I is independently 0 to 10₁ more preferably 0 to 5, more preferably 0 to 3, and most preferably 0 or 1.

Subject to the requirement that at least one of p and r≠ 0, preferably each p is

independently 0 to 10, more preferably 0 to 5, more preferably 0 to 3, and most preferably 0 or 1.

Subject to the requirement that at least one of p and r≠ 0, preferably each r is

Subject to the requirement that when n≠ 1 at least one of I and t≠ 0, preferably each t is independently 0 to 10, more preferably 0 to 5, more preferably 0 to 3, and most preferably 0 or 1.

According to formula II, z is independently 0 to 3. Preferably z is independently 0 to 1 , more preferably 0. According to formula II, n is independently 1 to 200. Suitably n is independently 1 to 100, preferably 1 to 50, more preferably 1 to 30, more preferably 1 to 20, more preferably 1 to 10, more preferably 1 to 5 and most preferably 1 to 3.

In particularly preferred embodiments n = 1. If n is greater than one, then the relevant groups within the bracketed portion is chosen independently for each occurrence of n. For example, each of the Ar groups and each of I, m, p, v, r, s, t and w is chosen independently for each occurrence of that Ar group or bracketed portion. Thus, for example, different triarylamine hole transporting portions and/or different electron transporting portions are possible for each occurrence of n.

According to formula II, each e is independently 0 or 1. In other words, the presence Of Ar₂ is optional (for each repeating unit comprising (Ar₂)_e). Preferably each e is independently 1.

Suitably the compound as described herein is an oligomer or polymer. For example, suitably n is greater than 1 so that n defines a repeating unit in the oligomer or polymer. Alternatively or additionally, each of v and w is independently greater than 1 so that there is a plurality of hole transporting and/or electron transporting portions.

Suitably any one or more of An, Ar₂, Ar₃, Ar_4a, Ar_4b, Ar₅, Ar₆, Ar_7aand Ar_7b is independently substituted. Suitable substituents include one or more of branched or unbranched alkyl, branched or unbranched heteroalkyl, branched or unbranched alkenyl, branched or unbranched heteroalkenyl, branched or unbranched alkynyl, branched or unbranched heteroalkynyl, branched or unbranched alkoxy, aryl and heteroaryl. Suitably, where such Ar groups are substituted, each of An, Ar₂, Ar_4a, Ar_4b, Ar₅, Ar₆, Ar_7a and Ar_7b is independently substituted by one or more of Ci_-2oalkyl, d_-2oalkoxy and C_5- ₅₀aryl, which substituents are optionally further substituted.

Suitably each Ar₃ is independently substituted with C_1-20alkyl, C_1-20alkoxy or C_5-50aryl.

Preferably each Ar₃ is independently substituted phenyl, more preferably C_5-20heteroaryl substituted phenyl, more preferably C_5-15 heteroaryl substituted phenyl, more preferably Cs-₁₅ N-containing heteroaryl and most preferably carbazoyl substituted phenyl. Thus, suitably Ar₃ is independently carbazoyl-phenylene and is optionally substituted.

Each Ar₅ is preferably independently substituted or unsubstituted phenylene, fluorenylene, spirobifluorenylene, spirosilabifluorenylene, indenofluorenylene. Reference herein to the optional substitution of Ar₅ is a reference to the optional presence of a substituent in addition to Ar₆.

In embodiments, each Ar₆ is independently substituted with an electron withdrawing group, R_Ew- Preferably each R_EW is selected independently from halo (especially -F and Cl), -CN, -NO₂, -CO, thionyl, sulphonyl and perfluoroalkyl. More preferably R_Ew is -CN.

Preferably the molecular weight Mw of the compound is in the range 1000 to 1 ,000,000 Da, more preferably 1000 to 500,000.

Embodiments of compounds of the present invention are luminescent, suitably

electroluminescent, and as such are useful in light emitting devices, for example organic electroluminescent devices. In a further aspect, the present invention provides a light emitting device comprising a compound as described herein. Suitably the organic electroluminescent device is or comprises an organic light emitting diode (OLED). That is, the compounds described herein are for use in organic light emitting diodes (OLEDs).

Thus, in another aspect, the present invention provides an organic electroluminescent device comprising a compound as described herein.

In a related aspect, the present invention provides an organic light emitting diode (OLED) comprising a compound as described herein. Suitably the compounds as described herein are used as an emissive layer for organic electroluminescent devices.

Thus, in another aspect, the present invention provides an organic electroluminescent device comprising an emissive layer, wherein the emissive layer comprises a compound as described herein.

Typically the compound of the present invention is present in an organic layer in such organic electroluminescent devices. Such embodiments may be used to form one or more of the emissive layer, a charge injection layer, a charge transport layer or a hole blocking layer. Typically the layer has the form of a thin film.

Thus, in another aspect, there is provided a thin film comprising a compound as described herein.

The thin film (e.g. a thin film forming the emissive layer) is typically a thin layer containing a compound as described herein, which layer may be formed to be in the order of from about 0.1 to about 1000 nm thick, preferably from about 1 to about 500 nm thick, more preferably from about 5 to about 250 nm thick, and most preferably from about 5 to about 100 nm thick.

The thin film may contain other components. For example, the thin film may comprise a host material such as a conductive organic chemical and a compound as described herein. The host material may be for example poly(9-vinylcarbazole) (PVK), 4,4'-N₁N'- dicarbazole-biphenyl (CBP), 4,4',4"-tri(N-carbazole)triphenylamine (TCTA), N,N'-diphenyl- N,N'-bis(3-methylphenyl)(1 ,1 '-biphenyl)-4,4'-diamine (TPD), N,N'-bis(1-naphthyl)-N,N'- diphenyl-1 ,1"-biphenyl-4,4'-diamine (NPB), 4,4',4"-tris(N,N-diphenyl-amino)

triphenylamine (TDATA), 1 ,3,5-tris(diphenylamino)benzene (TDAB), 1 ,3,5-tris(4-(di-2- pyridylamino)phenyl)benzene (TDAPB), TTBND, PPD, PTDATA, BFA-1T, p-dmDPS, p- DPA-TDAB, MTBDAB, spiro-mTTB, DBC, poly(1 ,4-phenylenevinylene), polyfluorene, poly(styrenesulfonic acid), poly(3,4-ethylenedioxythiophene), polyacetylene, polypyrrole, polyaniline, 3-phenyl-4(1'napthyl)-5-phenyl-1 ,2,4-triazole (TAZ), 2-(4-biphenyl)-5(4- tertbutyl-phenyl)-1 ,3,4,oxadiazole (PBD), 1 ,3,4-oxadiazole,2,2'-(1 ,3-phenylene)bis[5-[4- (1 ,1-dimethylethyl)phenyl]] (OXD-7) or poly[2-(6-cyano-6-methyl)heptyloxy-1 ,4- phenylene(CNPP), AIOq, AIq(CIq)₂, Al(Saph-q), AI(ODZ)₃, Ph₂Bq, Zn(BIZ)₂, Bepp₂, Bebq₂, Zn(ODZ)₂, spiro-PBD and BMB-3T.

The ratio of the host material to the compound as described herein may be from about 100:0.01 to about 100:30.

Alternatively, the thin film may comprise a compound as described herein as a host material and may further comprise an organic dye or phosphorescent emitter, for example, dyes such as 10-(2-benzothiazolyl)-1 ,1 ,7,7-tetramethyl-2,3,6,7-tetrahydro- 1 H,5H,11 H-[l]benzo-pyrano[6,7,8-ij]quinolizin-11-one, 3-(2-benzothiazolyl)-7- (diethylamino)-2H-1-benzopyran-2-one, 4-(dicyanomethylene)-2-t-butyl-6-(1 ,1 ,7,7- tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB), rubrene, 4-(dicyanomethylene)-2-t-butyl-6- (p-diphenylaminostyryl)-4H-pyran (DCTP), 3-(dicyanomethylene)-5,5-dimethyl-1-[(4- dimethylamino)styryl]cyclohexene (DCDDC), 6-methyl-3-[3-(1 ,1 ,6,6-tetramethyl-10-oxo- 2,3,5,6-tetrahydro-1 H,4H,10H-11-oxa-3a-azabenzo[de]- anthracen-9-yl)acryloyl]pyran-2,4-dione (AAAP), 6,13-diphenylpentacene (DPP) and

3-(N-phenyl-N-p-tolylamino)-9-(N-p-styrylphenyl-N-p-tolylamino)perylene [(PPA)(PSA)Pe- 1], 1 ,1'-dicyano-substituted bis-styrylnaphthalene derivative (BSN), or phosphorescent emitters such as PtOEP, lr(ppy)₃ or their derivatives.

The ratio of the compound as described herein to the dye or the phosphorescent emitter is from about 100:0.01 to about 1 :1.

The thin film may be formed on a suitable substrate, which may be any solid substrate, including quartz, glass, mica, a plastic substrate such as polyethylene terephthalate or polycarbonate, paper, metal, or silicon. The thin film may also be layered onto another layer when forming a multilayered device, or onto an electrode.

To form the thin film, the compound as described herein and any additional film

components may be dissolved in a suitable organic solvent. Suitable solvents include chloroform, toluene, xylene, ethyl benzoate, 1 ,1 ,2,2-tetrachloroethane, THF,

dichlorobenzene, mesitylene and mixtures of the aforesaid solvents.

The thin film may be formed on a suitable surface using standard deposition or coating methods including solution coating. Solution coating includes spin coating, casting, microgravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, spray coating, screen printing, flexo printing, offset printing and inkjet printing. The compounds as described herein and thin films containing such compounds may be used to construct electroluminescent devices, including single layer and multilayer devices. The compounds as described herein and thin films containing such compounds may form the emissive layer in an organic light emitting diode, the active layer in an organic thin film transistor or the active layer in an organic photovoltaic cell. Such devices and layers, as well as their construction, are known in the art.

In a further aspect, there is provided a device comprising an anode, a cathode and a thin film as described herein, the thin film being disposed between the anode and the cathode. In a further aspect, there is provided a device comprising: an anode; an emissive layer disposed on the anode, the emissive layer comprising a compound or thin film as described herein; and a cathode disposed on the emissive layer.

In another aspect, there is provided a device comprising: an anode; a hole transporting layer disposed on the anode; an emissive layer disposed on the hole transporting layer; an electron transporting layer disposed on the emissive layer; and a cathode disposed on the electron transporting layer; wherein at least one of the hole transporting layer, the emissive layer and the electron transporting layer comprises a compound or thin film as described herein.

In embodiments, the compounds described herein are used as active layers for photovoltaic cells.

In embodiments, the compounds described herein are used as a sensing layer for a chemical sensor or biosensor. In a further aspect, the present invention provides a chemical or bio sensor comprising a sensing layer wherein the sensing layer comprises a compound or thin film as described herein.

Suitably the devices referred to herein are display devices, for example a display panel.

Accordingly, a further aspect of the present invention provides a display device comprising a compound or thin film as described herein.

In a further aspect, the present invention provides a method of making a compound as described herein.

Definitions The term "triarylamine" as used herein pertains to a tertiary amine group NR₃ wherein each R is independently an aryl or aryl conjugatedly linked to the N. For example each R can be independently aryl, arylalkenylene or arylalkynylene. Preferred examples of the congujating linker group are vinylene and alkynylene: such that R is arylene vinylene or arylene ethynylene. In the context of the triarylamine being located in the backbone of a compound as described herein, two of the amine substituents R are bidentate and the discussion of aryl above applies to the corresponding arylene.

The term "backbone" as used herein will be familiar to the skilled reader and pertains to the main chain of the compound. The term "aryl" as used herein pertains to a monovalent aromatic radical derived from an aromatic compound by removal of one hydrogen atom. An aromatic compound is a cyclic compound having 4n+2 pi electrons where n is an integer equal to or greater than 0. In embodiments, the aryl group may have from 5 to 100 ring atoms, preferably 5 to 80, more preferably 5 to 50, more preferably 5 to 30 and most preferably 5 to 20 ring atoms.

Examples of aryls in the context of substituents are set out below.

The term "arylene" as used herein pertains to a bivalent aromatic radical derived from an aromatic compound by removal of two hydrogen atoms. An aromatic compound is a cyclic compound having 4n+2 pi electrons where n is an integer equal to or greater than 0. In embodiments, the arylene group may have from 5 to 100 ring atoms, preferably 5 to 80, more preferably 5 to 50, more preferably 5 to 30 and most preferably 5 to 20 ring atoms. Examples of arylenes in the context of substituents are set out below.

The term "heteroaryl" group as used herein pertains to an aryl group in which one or more of the backbone carbon atoms has been replaced with a hetero atom, for example one or more of N, O, S, Si or P.

The term "heteroarylene" as used herein pertains to an arylene group in which one or more of the backbone carbon atoms has been replaced with a hetero atom, for example one or more of N, O, S, Si or P.

The symbol "Ar" as used herein pertains generally to an aryl group, an arylene group, a heteroaryl group, a heteroarylene group, an aryl group and an adjacent vinylene group ("aryl vinylene"), an arylene group and an adjacent vinylene group ("arylene vinylene"), a heteroaryl group and an adjacent vinylene group ("heteroaryl vinylene"), a heteroarylene group and an adjacent vinylene group ("heteroarylene vinylene"), an aryl group and an adjacent ethynylene group ("aryl ethynylene"), an arylene group and an adjacent ethynylene group ("arylene ethynylene"), a heteroaryl group and an adjacent ethynylene group ("heteroaryl ethynylene"), or a heteroarylene group and an adjacent ethynylene group ("heteroarylene ethynylene"), or an aryl or arylene group and an adjacent nitrogen or amine group ("aminoaryl" or "aminoarylene"). As noted above, the term "aryl" includes heteroaryl, but heteroaryl is recited in the above list for completeness. The same applies to the corresponding heterarylene, heteroarylene vinylene and heteroarylene ethynylene.

It will be appreciated that where a particular Ar group is described as including an arylene or heterarylene group, but where such an arylene or heteroarylene occurs at an end of the molecule and is monovalent, that the particular group will be aryl or heteroaryl.

The term "vinylene" as used herein pertains to the bivalent radical represented by the formula -CH=CH-.

The term "ethynylene" as used herein pertains to the bivalent radical represented by the formula -C^-.

The term "alkyl" as used herein pertains to a branched or unbranched monovalent hydrocarbon group, having 1 to 20 carbon atoms. Similarly, an "alkylene" group as used herein refers to a branched or unbranched bivalent hydrocarbon group, having 1 to 20 carbon atoms. It will be understood that alkenyl and alkenylene are the respective terms for a monovalent and bivalent hydrocarbon radical that contains one or more double bonds and that alkynyl and alkynylene are the respective terms for a monovalent and bivalent hydrocarbon radical that contains one or more triple bonds.

The term "carbo," "carbyl," "hydrocarbo," and "hydrocarbyl," as used herein, pertain to compounds and/or groups which have only carbon and hydrogen atoms (but see

"carbocyclic" below).

The term "hetero," as used herein, pertains to compounds and/or groups which have at least one heteroatom, for example, multivalent heteroatoms (which are also suitable as ring heteroatoms) such as boron, silicon, nitrogen, phosphorus, oxygen, sulfur, and selenium (more commonly nitrogen, oxygen, and sulfur) and monovalent heteroatoms, such as fluorine, chlorine, bromine, and iodine. The term "saturated," as used herein, pertains to compounds and/or groups which do not have any carbon-carbon double bonds or carbon-carbon triple bonds.

The term "unsaturated," as used herein, pertains to compounds and/or groups which have at least one carbon-carbon double bond or carbon-carbon triple bond. Compounds and/or groups may be partially unsaturated or fully unsaturated.

The term "monodentate substituents," as used herein, pertains to substituents which have one point of covalent attachment.

The term "monovalent monodentate substituents," as used herein, pertains to substituents which have one point of covalent attachment, via a single bond. Examples of such substituents include halo, hydroxy, and alkyl. The term "bidentate substituents," as used herein, pertains to substituents which have two points of covalent attachment, and which act as a linking group between two other moieties. Examples of such substituents include alkylene and arylene.

The term "electron deficient" as used herein pertains to a pi system that has a deficiency of valence electrons such that the pi system (e.g. aryl group) suitably exhibits an electron withdrawing effect on the group to which it is attached. That is, it has a tendency to pull electrons away from the group to which it is attached.

Examples of electron deficient aryls include pyridyl, thiazolyl, oxadiazolyl and triazolyl, and their corresponding arylene structures.

The ability of an electron withdrawing aryl group to withdraw electrons from a

neighbouring aryl group tends to make an electron-withdrawing aryl group more electron- dense than a neighbouring aryl group that is not electron-withdrawing, similar to n-type materials used in a Si semiconductor, and thus more able to transport electrons.

Generally, electron-withdrawing groups are groups that create a positive or delta-positive region adjacent to the backbone so as to pull electrons from the backbone toward the substituent. Preferably the electron deficient pi system has one or more electron withdrawing substituents attached to it. Indeed, the electron deficiency of the group may be caused by the presence of the electron withdrawing substituent(s). Thus, in the case of Ar₆, the aryl or arylene pi system is electron deficient, for example as a result of attached electron withdrawing groups. Examples of electron withdrawing groups include -CN, -COOH, halo (especially -F and - Cl), -NO₂, -CO, perfluoroalkyl, ammonio, thionyl, sulfonyl, amido linked via the oxygen, pyridinium, phosphonium, pyridyl, thiazolyl, oxadiazolyl and triazolyl.

Functional groups may conveniently be classified as "electron withdrawing" (-6) or "electron donating" (+δ) groups, relative to hydrogen. Examples of electron donating groups include, but are not limited to, in approximate order of decreasing strength, -O^'

, -COO^", -CR₃, -CHR₂, -CH₂R, -CH₃, and -D. Examples of electron withdrawing groups include, but are not limited to, in approximate order of decreasing

strength, -NR₃ ⁺, -SR₂ ⁺, -NH₃ ⁺, -NO₂, -SO₂R, -CN, -SO₂Ar, -COOH, -F, -Cl₁ -Br, -I₁ -OAr, -C 0OR, -OR, -COR, -SH, -SR, -OH, -Ar, and -CH=CR₂ (wherein Ar denotes an aryl group).

See, for example, Ceppi et al., 1973, Tetrahedron Letters, p. 3627.

Substituents The phrase "optionally substituted," as used herein, pertains to a parent group which may be unsubstituted or which may be substituted.

Unless otherwise specified, the term "substituted," as used herein, pertains to a parent group which bears one or more substitutents. The term "substituent" is used herein in the conventional sense and refers to a chemical moiety which is covalently attached to, or if appropriate, fused to, a parent group. A wide variety of substituents are well known, and methods for their formation and introduction into a variety of parent groups are also well known. Examples of substituents are described in more detail below.

Alkyl: As noted above, the term "alkyl," as used herein, pertains to a monovalent moiety obtained by removing a hydrogen atom from a carbon atom of a hydrocarbon compound having from 1 to 20 carbon atoms (unless otherwise specified), which may be aliphatic or alicyclic, and which may be saturated or unsaturated (e.g., partially unsaturated, fully unsaturated). Thus, the term "alkyl" includes the sub-classes alkenyl, alkynyl, cycloalkyl, cycloalkyenyl, cylcoalkynyl, etc., discussed below.

In the context of alkyl groups, the prefixes (e.g., Ci_-4, C_1-7, C_1-20, C_2-7, C_3-7, etc.) denote the number of carbon atoms, or range of number of carbon atoms. For example, the term "C_1-4alkyl," as used herein, pertains to an alkyl group having from 1 to 4 carbon atoms. Examples of groups of alkyl groups include C_1-4alkyl ("lower alkyl"), C_1-7alkyl, and

Ci_-20alkyl. Note that the first prefix may vary according to other limitations; for example, for unsaturated alkyl groups, the first prefix must be at least 2; for cyclic and branched alkyl groups, the first prefix must be at least 3; etc.

Examples of (unsubstituted) saturated alkyl groups include, but are not limited to, methyl (C₁), ethyl (C₂), propyl (C₃), butyl (C₄), pentyl (C₅), hexyl (C₆), heptyl (C₇), octyl (C₈), nonyl (C₉), decyl (C₁₀), undecyl (C₁₁), dodecyl (C₁₂), tridecyl (C₁₃), tetradecyl (Ci₄), pentadecyl (C₁₅), and eicodecyl (C₂₀).

Examples of (unsubstituted) saturated linear alkyl groups include, but are not limited to, methyl (C₁), ethyl (C₂), n-propyl (C₃), n-butyl (C₄), n-pentyl (amyl) (C₅), n-hexyl (C₆), and n- heptyl (C₇), n-octyl (C8), n-decyl (C₁₀), n-dodecyl (C₁₂), n-tetradecyl (C₁₄), n-hexadecyl (C₁₆), n-octadecyl (C₁₈), and n-eicodecyl (C₂₀).

Examples of (unsubstituted) saturated branched alkyl groups include iso-propyl (C₃), iso-butyl (C₄), sec-butyl (C₄), tert-butyl (C₄), 3-pentyl, iso-pentyl (C₅), 3-methylbutyl, and neo-pentyl (C₅), 3,3-dimethylbutyl, 2-ethylbutyl, 4-methylpentyl, 2-hexyl, 2-heptyl, 2-octyl, 2-ethylhexyl, 3,7-dimethyloctyl, 2-butyloctyl, 2-hexyldecyl, 2-octyldodecyl.

Alkenyl: As noted above, the term "alkenyl," as used herein, pertains to an alkyl group having one or more carbon-carbon double bonds. Examples of groups of alkenyl groups include C_2-4alkenyl, C_2-7alkenyl, C₂-₂₀alkenyl.

Examples of (unsubstituted) unsaturated alkenyl groups include, but are not limited to, ethenyl (vinyl, -CH=CH₂), 1-propenyl (-CH=CH-CH₃), 2-propenyl (ally), -CH-CH=CH₂), isopropenyl (1-methylvinyl, -C(CH₃)=CH₂), butenyl (C₄), pentenyl (C₅), and hexenyl (C₆). Alkynyl: As noted above, the term "alkynyl," as used herein, pertains to an alkyl group having one or more carbon-carbon triple bonds. Examples of groups of alkynyl groups include C₂-₄alkynyl, C_2-7alkynyl, C₂.₂oalkynyl. Examples of (unsubstituted) unsaturated alkynyl groups include, but are not limited to, ethynyl (ethinyl, -C≡CH) and 2-propynyl (propargyl, -CH₂-C≡CH).

Cycloalkyl: The term "cycloalkyl," as used herein, pertains to an alkyl group which is also a cyclyl group; that is, a monovalent moiety obtained by removing a hydrogen atom from an alicyclic ring atom of a carbocyclic ring of a carbocyclic compound, which carbocyclic ring may be saturated or unsaturated (e.g., partially unsaturated, fully unsaturated), which moiety has from 3 to 20 carbon atoms (unless otherwise specified), including from 3 to 20 ring atoms. Thus, the term "cycloalkyl" includes the sub-classes cycloalkyenyl and cycloalkynyl. Preferably, each ring has from 3 to 7 ring atoms. Examples of groups of cycloalkyl groups include C_3-2ocycloalkyl, C_3-15cycloalkyl, C_3-10cycloalkyl, C_3-7cycloalkyl.

Examples of cycloalkyl groups include, but are not limited to, those derived from:

saturated monocyclic hydrocarbon compounds:

cyclopropane (C₃), cyclobutane (C₄), cyclopentane (C₅), cyclohexane (C₆), cycloheptane (C₇), methylcyclopropane (C₄), dimethylcyclopropane (C₅), methylcyclobutane (C₅), dimethylcyclobutane (C₆), methylcyclopentane (C₆), dimethylcyclopentane (C₇), methylcyclohexane (C₇), dimethylcyclohexane (C₈), menthane (C₁₀);

unsaturated monocyclic hydrocarbon compounds:

cyclopropene (C₃), cyclobutene (C₄), cyclopentene (C₅), cyclohexene (C₆),

methylcyclopropene (C₄), dimethylcyclopropene (C₅), methylcyclobutene (C₅), dimethylcyclobutene (C₆), methylcyclopentene (C₆), dimethylcyclopentene (C₇), methylcyclohexene (C₇), dimethylcyclohexene (C₈);

saturated polycyclic hydrocarbon compounds:

thujane (Ci₀), carane (C₁₀), pinane (Ci₀), bornane (C₁₀), norcarane (C₇), norpinane (C₇), norbomane (C₇), adamantane (C₁₀), decalin (decahydronaphthalene) (C₁₀);

unsaturated polycyclic hydrocarbon compounds:

camphene (C₁₀), limonene (C₁₀), pinene (C₁₀);

polycyclic hydrocarbon compounds having an aromatic ring:

indene (C₉), indane (e.g., 2,3-dihydro-1H-indene) (C₉), tetraline

(1 ,2,3,4-tetrahydronaphthalene) (C₁₀), acenaphthene (C₁₂), fluorene (C₁₃), phenalene (C₁₃), acephenanthrene (C₁₅), aceanthrene (C₁₆), cholanthrene (C₂₀). Alkylidene: The term "alkylidene," as used herein, pertains to a divalent monodentate moiety obtained by removing two hydrogen atoms from an aliphatic or alicyclic carbon atom of a hydrocarbon compound having from 1 to 20 carbon atoms (unless otherwise specified). Examples of groups of alkylidene groups include Ci_-2oalkylidene,

Ci_-7alkylidene, Ci_-4alkylidene.

Examples of alkylidene groups include, but are not limited to, methylidene (=CH₂), ethylidene (=CH-CH₃), vinylidene (=C=CH₂), isopropylidene (=C(CH₃)₂), cyclopentylidene, and benzylidene (=CH-Ph).

Alkylidyne: The term "alkylidyne," as used herein, pertains to a trivalent monodentate moiety obtained by removing three hydrogen atoms from an aliphatic or alicyclic carbon atom of a hydrocarbon compound having from 1 to 20 carbon atoms (unless otherwise specified). Examples of groups of alkylidyne groups include Ci_-2oalkylidyne,

C_1-7alkylidyne, Ci_-4alkylidyne.

Examples of alkylidyne groups include, but are not limited to, methylidyne (≡CH), ethylidyne (≡C-CH₃), and benzylidyne (≡C-Ph).

Carbocyclyl: The term "carbocyclyl," as used herein, pertains to a monovalent moiety obtained by removing a hydrogen atom from a ring atom of a carbocyclic compound, which moiety has from 3 to 20 ring atoms (unless otherwise specified). Preferably, each ring has from 3 to 7 ring atoms.

In this context, the prefixes (e.g., C_3-20, C_3-7, C_5-6, etc.) denote the number of ring atoms, or range of number of ring atoms. For example, the term "C_5-6carbocyclyl," as used herein, pertains to a carbocyclyl group having 5 or 6 ring atoms. Examples of groups of carbocyclyl groups include C_3-20Ca rbocyclyl, C_3-1ocarbocyclyl, C_5-10carbocyclyl,

C_3-7carbocyclyl, and C_5-7Ca rbocyclyl.

Examples of carbocyclic groups include, but are not limited to, those described above as cycloalkyl groups; and those described below as carboaryl groups. Heterocyclyl: The term "heterocyclyl," as used herein, pertains to a monovalent moiety obtained by removing a hydrogen atom from a ring atom of a heterocyclic compound, which moiety has from 3 to 20 ring atoms (unless otherwise specified), of which from 1 to 10 are ring heteroatoms. Preferably, each ring has from 3 to 7 ring atoms, of which from 1 to 4 are ring heteroatoms. In this context, the prefixes (e.g., C_3-20, C_3-7, C_5-6, etc.) denote the number of ring atoms, or range of number of ring atoms, whether carbon atoms or heteroatoms. For example, the term "C₅^heterocyclyl," as used herein, pertains to a heterocyclyl group having 5 or 6 ring atoms. Examples of groups of heterocyclyl groups include C_3-20heterocyclyl,

C_5-20heterocyclyl, C_3-15heterocyclyl, Cs-isheterocyclyl, C_3-12heterocyclyl, C_5-i₂heterocyclyl, C_3-10heterocyclyl, Cs-ioheterocyclyl, C_3-7heterocyclyl, C_5-7heterocyclyl, and Cs-βheterocyclyl.

Examples of heterocyclyl groups which are also heteroaryl groups are described below with aryl groups. Aryl: As noted above, the term "aryl," as used herein, pertains to a monovalent moiety obtained by removing a hydrogen atom from an aromatic ring atom of an aromatic compound, which moiety may have from 5 to 100 ring atoms (unless otherwise specified). Preferably, each ring has from 5 to 7 ring atoms. In this context, the prefixes (e.g., C_5-20, C_5-7, C_5-6, etc.) denote the number of ring atoms, or range of number of ring atoms, whether carbon atoms or heteroatoms. For example, the term "C_5-6aryl," as used herein, pertains to an aryl group having 5 or 6 ring atoms.

Examples of groups of aryl groups include C_5-20aryl, C_5-15aryl, C_5-i₂aryl, C_5-1oaryl, C_5-7aryl, C_5-6aryl, C₅aryl, and C₆aryl.

The ring atoms may be all carbon atoms, as in "carboaryl groups." Examples of carboaryl groups include C_5-i₀₀carboaryl, C_5-20Ca rboaryl, C_5-i₅carboaryl, C_5-i₂carboaryl,

C_5-i₀carboaryl, C₅.₇carboaryl, C_5-6Ca rboaryl, C₅carboaryl, and C₆carboaryl. Examples of carboaryl groups include, but are not limited to, those derived from benzene (i.e., phenyl) (C₆), naphthalene (C₁₀), azulene (Ci₀), anthracene (C₁₄), phenanthrene (C₁₄), naphthacene (C₁₈), and pyrene (C₁₆).

Examples of aryl groups which comprise fused rings, at least one of which is an aromatic ring, include, but are not limited to, groups derived from indane (e.g., 2,3-dihydro-1 H- indene) (C₉), indene (C₉), isoindene (C₉), tetraline (1 ,2,3,4-tetrahydronaphthalene (C₁₀), acenaphthene (Ci₂), fluorene (C13), phenalene (C₁₃), acephenanthrene (Ci₅), and aceanthrene (Ci₆).

Alternatively, the ring atoms may include one or more heteroatoms, as in "heteroaryl groups." Examples of heteroaryl groups include C_5-10oheteroaryl, C_5-2oheteroaryl,

C_5-i₅heteroaryl, C_5-12heteroaryl, C_5-10heteroaryl, C_5-7heteroaryl, C_5-6heteroaryl,

C₅heteroaryl, and C₆heteroaryl.

Examples of monocyclic heteroaryl groups include, but are not limited to, those derived from:

Ni: pyrrole (azole) (C₅), pyridine (azine) (C₆);

O₁: furan (oxole) (C₅);

Sv thiophene (thiole) (C₅);

N₁Oi: oxazole (C₅), isoxazole (C₅), isoxazine (C₆);

N₂Oi: oxadiazole (furazan) (C₅);

N₃O₁: oxatriazole (C₅);

N₁Si: thiazole (C₅), isothiazole (C₅);

N₂: imidazole (1 ,3-diazole) (C₅), pyrazole (1 ,2-diazole) (C₅), pyridazine (1 ,2-diazine) (C₆), pyrimidine (1 ,3-diazine) (C₆) (e.g., cytosine, thymine, uracil), pyrazine (1 ,4-diazine) (C₆); N₃: triazole (C₅), triazine (C₆); and,

N₄: tetrazole (C₅).

Examples of heterocyclic groups (some of which are also heteroaryl groups) which comprise fused rings, include, but are not limited to:

Cgheterocyclic groups (with 2 fused rings) derived from benzofuran (O₁), isobenzofuran (O₁), indole (N₁), isoindole (Ni), indolizine (N₁), indoline (Ni), isoindoline (Ni), purine (N₄) (e.g., adenine, guanine), benzimidazole (N₂), indazole (N₂), benzoxazole (N₁O₁), benzisoxazole (N₁O₁), benzodioxole (O₂), benzofurazan (N₂Oi), benzotriazole (N₃), benzothiofuran (Si), benzothiazole (N₁S₁), benzothiadiazole (N₂S);

C₁₀heterocyclic groups (with 2 fused rings) derived from chromene (O₁), isochromene (O₁), chroman (O₁), isochroman (O₁), benzodioxan (O₂), quinoline (Ni), isoquinoline (Ni), quinolizine (N₁), benzoxazine (N₁O₁), benzodiazine (N₂), pyridopyridine (N₂), quinoxaline (N₂), quinazoline (N₂), cinnoline (N₂), phthalazine (N₂), naphthyridine (N₂), pteridine (N₄); Cnheterocylic groups (with 2 fused rings) derived from benzodiazepine (N₂);

C₁₃heterocyclic groups (with 3 fused rings) derived from carbazole (N₁), dibenzofuran (O₁), dibenzothiophene (S₁), carboline (N₂), perimidine (N₂), pyridoindole (N₂); and, Ci₄heterocyclic groups (with 3 fused rings) derived from acridine (Ni), xanthene (O₁), thioxanthene (Si), oxanthrene (O₂), phenoxathiin (O₁S₁), phenazine (N₂), phenoxazine (N₁O₁), phenothiazine (N₁S₁), thianthrene (S₂), phenanthridine (N₁), phenanthroline (N₂), phenazine (N₂).

Heterocyclic groups (including heteroaryl groups) which have a nitrogen ring atom in the form of an -NH- group may be N-substituted, that is, as -NR-. For example, pyrrole may be N-methyl substituted, to give N-methylpyrrole. Examples of N-substitutents include, but are not limited to C_1-7alkyl, C_3-20heterocyclyl, C_5-2oaryl, and acyl groups.

Heterocyclic groups (including heteroaryl groups) which have a nitrogen ring atom in the form of an -N= group may be substituted in the form of an N-oxide, that is, as -N(→O)= (also denoted -N⁺(→O^~)=). For example, quinoline may be substituted to give quinoline N- oxide; pyridine to give pyridine N-oxide; benzofurazan to give benzofurazan N-oxide (also known as benzofuroxan).

The above groups, whether alone or part of another substituent, may themselves optionally be substituted with one or more groups selected from themselves and the additional substituents listed below.

Hydrogen: -H. Note that if the substituent at a particular position is hydrogen, it may be convenient to refer to the compound or group as being "unsubstituted" at that position.

Halo: -F, -Cl, -Br, and -I.

Hydroxy: -OH.

Ether: -OR, wherein R is an ether substituent, for example, a C_1-7alkyl group (also referred to as a C_1-7alkoxy group, discussed below), a C_3-20heterocyclyl group (also referred to as a C_3-20heterocyclyloxy group), or a C_5-20aryl group (also referred to as a Cs^oaryloxy group), preferably a C_1-7alkyl group.

Alkoxy: -OR, wherein R is an alkyl group, for example, a C_1-7alkyl group. Examples of C_1-7alkoxy groups include, but are not limited to, -OMe (methoxy), -OEt (ethoxy), -O(nPr) (n-propoxy), -O(iPr) (isopropoxy), -O(nBu) (n-butoxy), -O(sBu) (sec-butoxy), -O(iBu) (isobutoxy), and -O(tBu) (tert-butoxy). Acetal: -CH(OR¹ )(OR²), wherein R¹ and R² are independently acetal substituents, for example, a C_1-7alkyl group, a C_3-2oheterocyclyl group, or a C_5-2oaryl group, preferably a Ci_-7alkyl group, or, in the case of a "cyclic" acetal group, R¹ and R², taken together with the two oxygen atoms to which they are attached, and the carbon atoms to which they are attached, form a heterocyclic ring having from 4 to 8 ring atoms. Examples of acetal groups include, but are not limited to, -CH(OMe)₂, -CH(OEt)₂, and -CH(OMe)(OEt).

Oxo (keto, -one): =0.

Thione (thioketone): =S. lmino (imine): =NR, wherein R is an imino substituent, for example, hydrogen, C_1-7alkyl group, a C_3-20heterocyclyl group, or a C_5-20aryl group, preferably hydrogen or a C_1-7alkyl group. Examples of imine groups include, but are not limited to, =NH, =NMe, =NEt, and =NPh.

Formyl (carbaldehyde, carboxaldehyde): -C(=O)H. Acyl (keto): -C(=O)R, wherein R is an acyl substituent, for example, a Ci_-7alkyl group (also referred to as C_1-7alkylacyl or C_1-7alkanoyl), a C_3-20heterocyclyl group (also referred to as C_3-20heterocyclylacyl), or a C_5-20aryl group (also referred to as C₅.₂₀arylacyl), preferably a Ci_-7alkyl group. Examples of acyl groups include, but are not limited to, -C(=0)CH₃ (acetyl), -C(=O)CH₂CH₃ (propionyl), -C(=O)C(CH₃)₃ (t-butyryl), and -C(=O)Ph (benzoyl, phenone).

Carboxy (carboxylic acid): -C(=O)OH.

Thiocarboxy (thiocarboxylic acid): -C(=S)SH.

Thiolocarboxy (thiolocarboxylic acid): -C(=O)SH.

Thionocarboxy (thionocarboxylic acid): -C(=S)OH. Ester (carboxylate, carboxylic acid ester, oxycarbonyl): -C(=0)0R, wherein R is an ester substituent, for example, a C_1-7alkyl group, a C_3-20heterocyclyl group, or a C_5-20aryl group, preferably a d_-7alkyl group. Examples of ester groups include, but are not limited to, -C(=0)0CH₃, -C(=O)OCH₂CH₃, -C(=O)OC(CH₃)₃, and -C(=O)OPh.

Acyloxy (reverse ester): -0C(=0)R, wherein R is an acyloxy substituent, for example, a C_1-7alkyl group, a C_3-2oheterocyclyl group, or a C_5-2oaryl group, preferably a C_1-7alkyl group. Examples of acyloxy groups include, but are not limited to, -0C(=0)CH₃

(acetoxy), -OC(=O)CH₂CH₃, -OC(=O)C(CH₃)₃, -OC(=O)Ph, and -OC(=O)CH₂Ph.

Oxycarboyloxy: -OC(=O)OR, wherein R is an ester substituent, for example, a C_1-7alkyl group, a C_3-20heterocyclyl group, or a C₅.₂₀aryl group, preferably a Ci_-7alkyl group.

Examples of ester groups include, but are not limited

to, -0C(=0)0CH₃, -OC(=O)OCH₂CH₃, -OC(=O)OC(CH₃)₃, and -OC(=O)OPh.

Amino: -NR¹R², wherein R¹ and R² are independently amino substituents, for example, hydrogen, a Ci_-7alkyl group (also referred to as Ci_-7alkylamino or di-Ci_-7alkylamino), a C_3-20heterocyclyl group, or a C_5-20aryl group, preferably H or a Ci_-7alkyl group, or, in the case of a "cyclic" amino group, R¹ and R², taken together with the nitrogen atom to which they are attached, form a heterocyclic ring having from 4 to 8 ring atoms. Amino groups may be primary (-NH₂), secondary (-NHR¹), or tertiary (-NHR¹R²), and in cationic form, may be quaternary (-⁺NR¹R²R³). Examples of amino groups include, but are not limited to, -NH₂, -NHCH₃, -NHC(CH₃)₂, -N(CH₃)₂, -N(CH₂CH₃)₂, and -NHPh. Examples of cyclic amino groups include, but are not limited to, aziridino, azetidino, pyrrolidino, piperidino, piperazino, morpholino, and thiomorpholino. Amido (carbamoyl, carbamyl, aminocarbonyl, carboxamide): -C(=O)NR¹R², wherein R¹ and R² are independently amino substituents, as defined for amino groups. Examples of amido groups include, but are not limited

to, -C(=O)NH₂, -C(=O)NHCH₃, -C(=O)N(CH₃)₂, -C(=O)NHCH₂CH₃,

and -C(=O)N(CH₂CH₃)₂, as well as amido groups in which R¹ and R², together with the nitrogen atom to which they are attached, form a heterocyclic structure as in, for example, piperidinocarbonyl, morpholinocarbonyl, thiomorpholinocarbonyl, and piperazinocarbonyl.

Thioamido (thiocarbamyl): -C(=S)NR¹R², wherein R¹ and R² are independently amino substituents, as defined for amino groups. Examples of amido groups include, but are not limited to, -C(=S)NH₂, -C(=S)NHCH₃, -C(=S)N(CH₃)_2l and -C(=S)NHCH₂CH₃. Acylamido (acylamino): -NR¹C(=O)R², wherein R¹ is an amide substituent, for example, hydrogen, a C_1-7alkyl group, a C_3-2oheterocycIyl group, or a C_5-2oaryl group, preferably hydrogen or a C_1-7alkyl group, and R² is an acyl substituent, for example, a Ci_-7alkyl group, a C_3-2oheterocyclyl group, or a C_5-20aryl group, preferably hydrogen or a C_1-7alkyl group. Examples of acylamide groups include, but are not limited to, -NHC(=O)CH₃ , -NHC(=O)CH₂CH₃, and -NHC(=O)Ph. R¹ and R² may together form a cyclic structure, as in, for example, succinimidyl, maleimidyl, and phthalimidyl:

succinimidyl maleimidyl phthalimidyl Aminocarbonyloxy: -OC(=O)NR¹R², wherein R¹ and R² are independently amino substituents, as defined for amino groups. Examples of aminocarbonyloxy groups include, but are not limited to, -OC(=O)NH₂, -OC(=O)NHMe, -OC(=O)NMe₂, and -OC(=O)NEt₂.

Ureido: -N(R¹JCONR²R³ wherein R² and R³ are independently amino substituents, as defined for amino groups, and R1 is a ureido substituent, for example, hydrogen, a

C_1-7alkyl group, a C_3-20heterocyclyl group, or a C_5-20aryl group, preferably hydrogen or a

C_1-7alkyl group. Examples of ureido groups include, but are not limited to, -NHCONH₂, -

NHCONHMe, -NHCONHEt, -NHCONMe₂, -NHCONEt₂, -NMeCONH₂, -

NMeCONHMe, -NMeCONHEt, -NMeCONMe₂, and -NMeCONEt₂.

Tetrazolyl: a five membered aromatic ring having four nitrogen atoms and one carbon atom,

Imino: =NR, wherein R is an imino substituent, for example, for example, hydrogen, a C_1-7alkyl group, a C_3-20heterocyclyl group, or a C_5-20aryl group, preferably H or a C_1-7alkyl group. Examples of imino groups include, but are not limited to, =NH, =NMe, and =NEt.

Amidine (amidino): -C(=NR)NR₂, wherein each R is an amidine substituent, for example, hydrogen, a C_1-7alkyl group, a C_3-20heterocyclyl group, or a C_5-20aryl group, preferably H or a Ci_-7alkyl group. Examples of amidine groups include, but are not limited to, -C(=NH)NH₂, -C(=NH)NMe₂, and -C(=NMe)NMe₂.

Nitro: -NO₂.

Nitroso: -NO.

Cyano (nitrile, carbonitrile): -CN. Isocyano: -NC. Cyanato: -OCN.

Isocyanato: -NCO.

Thiocyano (thiocyanato): -SCN. lsothiocyano (isothiocyanato): -NCS. In many cases, substituents are themselves substituted.

For example, a Ci_-7alkyl group may be substituted with, for example:

hydroxy (also referred to as a hydroxy-Ci_-7alkyl group);

halo (also referred to as a halo-Ci_-7alkyl group);

amino (also referred to as a amino-C_1-7alkyl group);

carboxy (also referred to as a carboxy-C_1-7alkyl group);

C_1-7alkoxy (also referred to as a Ci_-7alkoxy-C_1-7alkyl group);

C_5-20aryl (also referred to as a C_5-2oaryl-Ci_-7alkyl group). Similarly, a C_5-20aryl group may be substituted with, for example:

hydroxy (also referred to as a hydroxy-C_5-20aryl group);

halo (also referred to as a halo-C_5-20aryl group);

amino (also referred to as an amino-C₅.₂oaryl group, e.g., as in aniline);

carboxy (also referred to as an carboxy-C_5-20aryl group, e.g., as in benzoic acid); C_1-7alkyl (also referred to as a Ci_-7alkyl-C_5-2oaryl group, e.g., as in toluene);

Ci_-7alkoxy (also referred to as a Ci_-7alkoxy-C_5-20aryl group, e.g., as in anisole); C_5-2oaryl (also referred to as a C5-₂oaryl-C_5-2Oaryl, e.g., as in biphenyl).

These and other specific examples of such substituted-substituents are described below. Hydroxy-C_1-7alkyl: The term " hydroxy-Ci_-7alkyl," as used herein, pertains to a Ci_-7alkyl group in which at least one hydrogen atom (e.g., 1 , 2, 3) has been replaced with a hydroxy group. Examples of such groups include, but are not limited

to, -CH₂OH, -CH₂CH₂OH, and -CH(OH)CH₂OH. Halo-Ci_-7alkyl group: The term " halo-d_-7alkyl," as used herein, pertains to a C_1-7alkyl group in which at least one hydrogen atom (e.g., 1 , 2, 3) has been replaced with a halogen atom (e.g., F, Cl, Br, I). If more than one hydrogen atom has been replaced with a halogen atom, the halogen atoms may independently be the same or different. Every hydrogen atom may be replaced with a halogen atom, in which case the group may conveniently be referred to as a Ci_-7perhaloalkyl group." Examples of such groups include, but are not limited to, -CF₃, -CHF₂, -CH₂F, -CCI₃, -CBr₃, -CH₂CH₂F, -CH₂CHF₂, and -CH₂CF₃.

Amino-Ci_-7alkyl: The term " amino-C_1-7alkyl," as used herein, pertains to a C_1-7alkyl group in which at least one hydrogen atom (e.g., 1 , 2, 3) has been replaced with an amino group. Examples of such groups include, but are not limited to, -CH₂NH₂, -CH₂CH₂NH₂, and -CH₂CH₂N(CHa)₂.

Carboxy-Ci_-7alkyl: The term "carboxy-C_1-7alkyl," as used herein, pertains to a Ci_-7alkyl group in which at least one hydrogen atom (e.g., 1 , 2, 3) has been replaced with a carboxy group. Examples of such groups include, but are not limited to, -CH₂COOH and -CH₂CH₂COOH.

C_1-7alkoxy-C_1-7alkyl: The term "C_1-7alkoxy-C_1-7alkyl," as used herein, pertains to a Ci_-7alkyl group in which at least one hydrogen atom (e.g., 1 , 2, 3) has been replaced with a

C^alkoxy group. Examples of such groups include, but are not limited

to, -CH₂OCH₃, -CH₂CH₂OCH₃, and ,-CH₂CH₂OCH₂CH₃

C_5-20aryl-Ci_-7alkyl: The term "C_5-20aryl-C_1-7alkyl," as used herein, pertains to a C_1-7alkyl group in which at least one hydrogen atom (e.g., 1 , 2, 3) has been replaced with a C_5- ₂₀aryl group. Examples of such groups include, but are not limited to, benzyl (phenylmethyl, PhCH₂-), benzhydryl (Ph₂CH-), trityl (triphenylmethyl, Ph₃C-), phenethyl (phenylethyl, Ph-CH₂CH₂-), styryl (Ph-CH=CH-), cinnamyl (Ph-CH=CH-CH₂-).

Hydroxy-C_5-20aryl: The term " hydroxy-C_5-2oaryl," as used herein, pertains to a C_5-20aryl group in which at least one hydrogen atom (e.g., 1 , 2, 3) has been substituted with an hydroxy group. Examples of such groups include, but are not limited to, those derived from: phenol, naphthol, pyrocatechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol.

Halo-C_5-20aryl: The term "halo-Cs-_∑oaryl," as used herein, pertains to a C_5-20aryl group in which at least one hydrogen atom (e.g., 1 , 2, 3) has been substituted with a halo (e.g., F, Cl₁ Br, I) group. Examples of such groups include, but are not limited to, halophenyl (e.g., fluorophenyl, chlorophenyl, bromophenyl, or iodophenyl, whether ortho-, meta-, or para- substituted), dihalophenyl, trihalophenyl, tetrahalophenyl, and pentahalophenyl. Ci_-7alkyl-C_5-2oaryl: The term "C_1-7alkyl-C_5-20aryl," as used herein, pertains to a C_5-2oaryl group in which at least one hydrogen atom (e.g., 1 , 2, 3) has been substituted with a Ci_-7alkyl group. Examples of such groups include, but are not limited to, tolyl (from toluene), xylyl (from xylene), mesityl (from mesitylene), and cumenyl (or cumyl, from cumene), and duryl (from durene).

Hydroxy-Ci_-7alkoxy: -OR, wherein R is a hydroxy-C_1-7alkyl group. Examples of

hydroxy-Ci_-7alkoxy groups include, but are not limited to, -OCH₂OH, -OCH₂CH₂OH, and -OCH₂CH₂CH₂OH. Halo-Ci_-7alkoxy: -OR, wherein R is a halo-C_1-7alkyl group. Examples of halo-C_1-7alkoxy groups include, but are not limited

to, -OCF₃, -OCHF₂, -OCH₂F, -OCCI₃, -OCBr₃, -OCH₂CH₂F, -OCH₂CHF₂, and -OCH₂CF₃.

Carboxy-Ci_-7alkoxy: -OR, wherein R is a carboxy-C_1-7alkyl group. Examples of carboxy- C_1-7alkoxy groups include, but are not limited to, -OCH₂COOH, -OCH₂CH₂COOH, and -OCH₂CH₂CH₂COOH.

Ci_-7alkoxy-C_1-7alkoxy: -OR, wherein R is a Ci_-7alkoxy-C_1-7alkyl group. Examples of Ci_-7alkoxy-C_1-7alkoxy groups include, but are not limited to, -OCH₂OCH₃, -OCH₂CH₂OCH₃, and -OCH₂CH₂OCH₂CH₃. C_5-2oaryl-C_1-7alkoxy: -OR, wherein R is a C_5-2oaryl-Ci_-7alkyl group. Examples of such groups include, but are not limited to, benzyloxy, benzhydryloxy, trityloxy, phenethoxy, styryloxy, and cimmamyloxy. Ci_-7alkyl-C_5-2oaryloxy: -OR, wherein R is a Ci_-7alkyl-C_5-2oaryl group. Examples of such groups include, but are not limited to, tolyloxy, xylyloxy, mesityloxy, cumenyloxy, and duryloxy.

Amino-C_1-7alkyl-amino: The term "amino-Ci_-7alkyl-amino," as used herein, pertains to an amino group, -NR¹R², in which one of the substituents, R¹ or R², is itself a amino-Ci_-7alkyl group (-C_1-7alkyl-NR³R⁴). The amino-Ci_-7alkylamino group may be represented, for example, by the formula -NR¹-Ci_-7alkyl-NR³R⁴. Examples of such groups include, but are not limited to, groups of the formula -NR¹(CH₂)_nNR¹R², where n is 1 to 6 (for

example, -NHCH₂NH₂, -NH(CH₂)₂NH₂, -NH(CH₂)₃NH₂, -NH(CH₂)₄NH₂, -NH(CH₂)₅NH₂, -NH (CH₂J₆NH₂), -NHCH₂NH(Me), -NH(CH₂)₂NH(Me), -NH(CH₂)₃NH(Me), -NH(CH₂J₄NH(Me), - NH(CH₂)₅NH(Me), -NH(CH₂J₆NH(Me), -NHCH₂NH(Et), -NH(CH₂J₂NH(Et), -NH(CH₂)₃NH(Et ), -NH(CH₂)₄NH(Et), -NH(CH₂)₅NH(Et), and -NH(CH₂J₆NH(Et).

Certain Preferred Substituents

In one preferred embodiment, the substituent(s), often referred to herein as R, are independently selected from: halo; hydroxy; ether (e.g., C_1-7alkoxy); formyl; acyl (e.g., C_1-7alkylacyl , C_5-20arylacyl); acylhalide; carboxy; ester; acyloxy; amido; acylamido;

thioamido; tetrazolyl; amino; nitro; nitroso; azido; cyano; isocyano; cyanato; isocyanato; thiocyano; isothiocyano; sulfhydryl; thioether (e.g., C_1-7alkylthio); sulfonic acid; sulfonate; sulfone; sulfonyloxy; sulfinyloxy; sulfamino; sulfonamino; sulfinamino; sulfamyl;

sulfonamido; C_1-7alkyl (including, e.g., unsubstituted Ci_-7alkyl, Ci_-7haloalkyl,

C_1-7hydroxyalkyl, Ci_-7carboxyalkyl, C_1-7aminoalkyl, C_5-20aryl-C_1-7alkyl); C_3-20heterocyclyl; or C_5-20aryl (including, e.g., C_5-2ocarboaryl, C_5-2oheteroaryl, C_1-7alkyl-C_5-20aryl and

C₅.₂₀haloaryl)).

In one preferred embodiment, the substituent(s), often referred to herein as R, are independently selected from: -F, -Cl, -Br, -I₁ -OH, -OMe, -OEt, -SH, - SMe, -SEt, -C(=O)Me, -C(=O)OH, -C(=O)OMe, -CONH₂, -CONHMe, -NH₂, -NMe₂, - NEt₂, -N(IiPr)₂, -N(JPr)₂, -CN, -

NO₂, -Me, -Et, -CF₃, -OCF₃, -CH₂OH₁ -CH₂CH₂OH, -CH₂NH₂, -CH₂CH₂NH₂, and -Ph. In one preferred embodiment, the substituent(s), often referred to herein as R, are independently selected from: hydroxy; ether (e.g., C_1-7alkoxy); ester; amido; amino; and, Ci_-7alkyl (including, e.g., unsubstituted C_1-7alkyl, Ci_-7haloalkyl, Ci_-7hydroxyalkyl,

C_1-7carboxyalkyl, C_1-7aminoalkyl, C_5-2oaryl-C_1-7alkyl).

BRIEF DESCRIPTION OF THE FIGURES

Embodiments of the invention will now be described with reference to the accompanying figures, in which:

Figure 1 illustrates the hole transporting, electron transporting and spacer portions of the compound of formula I;

Figure 2 illustrates the backbone portion of the compound of formula I;

Figure 3 shows a schematic diagram of an OLED device, being an embodiment of the present invention;

Figure 4 shows the TGA plots of PCPC4 and PTCC4;

Figure 5 shows the DSC plots of PCPC4 and PTCC4;

Figure 6 shows the UV-vis absorption and photoluminescence (PL) spectra of PCPC4 and PTCC4 in toluene;

Figure 7 shows the thin film UV-vis absorption and photoluminescence (PL) spectra of PCPC4 and PTCC4;

Figure 8 shows the electroluminescence (EL) spectrum of PCPC4;

Figure 9A and Figure 9B show the I-V-L characteristics and current efficiency of PCPC4 respectively;

Figure 10 shows the electroluminescence (EL) spectrum of PTCC4; and

Figure 11 A and Figure 11 B show the I-V-L characteristics and current efficiency of PTCC4 respectively.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention is further described with reference to the following experiments and examples (some of which are comparative examples).

Whilst a number of features are referred to in the examples in the context of specific combinations of features and, where appropriate, with those features having particular values, it is to be understood that any one of those features can be present in other embodiments of the invention optionally in combination with other features. Similarly, any particular values associated with a feature may be adjusted in accordance with the general disclosures given herein. Instruments and characterisation methods

Nuclear magnetic resonance (NMR) spectra were collected on a Bruker DPX 400 MHz spectrometer using chloroform-d or dichloromethane-d₂ as the solvent and

tetramethylsilane (TMS) as an internal standard.

Matrix-Assisted Laser Desorption/lonization Time-Of-Flight (MALDI-TOF) mass spectra were obtained on a Bruker Autoflex TOF/TOF instrument.

Differential scanning calorimetry (DSC) was carried out under nitrogen on a TA Instrument DSC 2920 module (scanning rate of 20 °C/min).

Thermal gravimetric analysis (TGA) was carried out using a TA Instrument TGA 2050 module (heating rate of 20 °C/min). Cyclic voltammetry (CV) experiments were performed on an Autolab potentiostat (model PGSTAT30). All CV measurements were recorded in dichloromethane with 0.1 M tetrabutylammonium hexafluorophosphate as supporting electrolyte (scan rate of 50 mV/s) using a conventional three electrode configuration consisting of a platinum wire working electrode, a gold counter electrode, and a Ag/AgCI in 3 M KCI reference electrode. The measured potentials were converted to SCE (saturated calomel electrode) and the corresponding ionization potential (IP) and electron affinity (EA) values were derived from the onset redox potentials, based on -4.4 eV as the SCE energy level relative to vacuum (EA = E_red-onset + 4.4 eV, IP = E₀^_nse, + 4.4 eV). The absorption spectra were recorded on a Shimadzu UV-3101 PC UV-vis-NIR spectrophotometer using dichloromethane solution, except where stated otherwise, with concentration ranging from 1.8 x 10^"6 to 3.1 * 10^"6 M.

Synthesis The following schemes show the methodology used to produce the copolymers of the present invention.

Scheme 1. Synthesis of compound 3

toluene

4 5

Scheme 2. Synthesis of compound 5

Scheme 3. Synthesis of compound 9

10

Pd(PPh₃)₄/K₂CO₃ tolueπe/H₂O

PCSF m : n = 1 : 0 PCPC4a m : n = 2 : 1 PCPC4 m : n = 1 : 1 PCPC4b m : n = 1 : 2 PCPF m : n = 0 : 1 Scheme 4. Synthesis of copolymers

10

Pd(PPh₃)₄/K₂CO₃ toluene/H₂O

PTCC4a m n = 2:

PTCC4 m n = 1 :

PTCC4b m n = 1 :

PTCPF m n = 0:

Scheme 5. Synthesis of copolymers

Example 1 - Synthesis of 4,4'-(2^l,7^l-dibromo-9,9'-spirobi[fluorene]-2,7-diyl)dibenzonitrile (3)

Step 1 - Synthesis of 4,4¹-(9,9'-spirobi[fluorene]-2,7-diyl)dibenzonitrile (2)

To a mixture of 2,7-dibromo-9,9'-spirobi[fluorene] (1 ) (1.76 g, 3.7 mmol) and 4- cyanophenylboronic acid (2.04 g, 13.9 mmol ), (PPh₃)₄Pd (0.23 g, 0.20 mmol) was added in a glovebox. Toluene (32 ml.) and 2M Na₂CO₃ (16 mL) was added into the mixture and heated to reflux with stirring in the dark for 24 h under the protection of nitrogen. After cooling to room temperature, the organic layer was separated and the aqueous layer was extracted with ethyl acetate (8OmL) twice. The combined organic layer was washed with water, brine and dried over sodium sulfate. The solvent was removed under reduced pressure and the crude product was purified by silica gel column chromatography with n- hexane/ethyl acetate (5:1 ) as eluent to give (2) as a white powder (1.94g, 77.5 %). ¹H NMR (CDCI₃, 400 MHz, ppm) δ 7.98(d, 2H, J=8.0 Hz), 7.89 (d, 2H, J= 7.6 Hz ), 7.64 (dd, 2H, J= 1.6, 8.0 Hz), 7.60 (d, 4H, J= 8.4 Hz), 7.52 (d, 4H, J = 8.4Hz), 7.41 (t, 2H), 7.14(t, 2H), 6.94 (s, 2H), 6.80(d, 2H, J= 7.6 Hz). Step 2 - Synthesis of 4,4'-(2¹,7¹-dibromo-9,9'-spirobi[fluorene]-2,7-diyl)dibenzonitrile (3)

To a solution of 4,4¹-(9_>9'-spirobi[fluorene]-2,7-diyl)dibenzonitrile (2) (1.04 g , 2.0 mmol) in 25 ml. of dichloromethane at 0^°C, 40mg (0.3mmol) of iron(lll) chloride was added. A solution of bromine (0.71 g, 4.4 mmol) in 10 ml. of dichloromethane was added into the stirring mixture dropwise at 0^°C. After stirring at room temperature for 48 h, the solution was cooled to 0^°C again and an aqueous solution of sodium sulfite was added slowly till the dark color disappeared. The organic layer was separated and the aqueous layer was extracted twice with dichloromethane (100 ml_). The combined organic layer was washed with brine and dried over sodium sulfate. The solvent was removed and the residue was purified by column chromatography eluting with n-hexane/ethyl acetate (5:1 ) followed by re-crystallization with ethanol to give 3 (1.12g, 82.5 %).¹H NMR (CDCI₃, 400 MHz, ppm) δ 7.99(d, 2H, J=8.0 Hz), 7.72 (d, 2H₁ J= 8.0 Hz ), 7.69 (dd, 2H, J= 1.6, 8.0 Hz), 7.64 (d, 4H, J = 8.4Hz), 7.53-7.57 (m, 6H), 6.91(dd, 2H. J = 2.0, 6.8Hz). ¹³C NMR (CDCI₃, 100 MHz, ppm) δ 149.75, 149.66, 144.93, 141.37, 139.72, 139.67, 132.47, 131.64, 127.90, 127.72, 127.36, 122.75, 122.20, 121.73, 121.23, 118.74, 111.09, 65.71.

Example 2 - Synthesis of N-(4-(9H-carbazol-9-yl)phenyl)-4-bromo-N-(4- bromophenyl)aniline (5) A mixture of 4-carbazol-9-yl-phenylamine (4) (1.29 g, 5.0 mmol), 1-bromo-4-iodobenzene (3.39 g, 12.0 mmol), Pd(OAc)₂ (224.5 mg, 1.0 mmol), 1 ,1'-bis(diphenylphosphino)- ferrocene(1.11 g, 2.0 mmol) and sodium terf-butoxide (1.92 g, 20.0 mmol) was purged with nitrogen and dry toluene (2OmL) was added. The mixture was refluxed for 24 h in the dark and cooled to room temperature. The suspension was dispersed in 100 mL toluene and filtered to remove the solid. The filtrate was washed with water, brine and dried over sodium sulfate. After the solvent was removed, the residue was purified by column chromatography with n-hexane/dichloromethane (4:1 ) to give 5 as white solid (464 mg, 16.3 %).¹H NMR (CD₂CI₂, 400 MHz, ppm) <J8.16 (d, 2H, J= 7.6 Hz), 7.45 (m, 10H), 7.30(m, 4H), 7.09 (d, 4H, 8.8Hz). ¹³C NMR (CDCI₃, 100 MHz, ppm) δ 146.39, 146.11 , 141.00, 132.66, 132.50, 128.05, 125.90, 125.88, 124.99, 123.25, 120.18, 119.85, 115.95, 109.72.

Example 3 - Synthesis of N-(4-((3,6-Di-9H-carbazol-9-yl))phenyl)-4-bromo-N-(4- bromophenyl)aniline (9) Step 1 - Synthesis of 3,6-(di-9H-carbazol-9-yl)-9-(4-nitrophenyl)-9H-carbazole (7)

A mixture of 3,6-dibromo-9-(4-nitrophenyl)-9H-carbazole (6) (4.3Og, 9.6 mmol), carbazole(3.67g, 21.9 mmol), copper(l) iodide(375mg, 1.97 mmol), 1 ,10- phenanthroline(710mg, 3.94 mmol ) and potassium carbonate (5.98 g, 43.3 mmol) was purged with nitrogen and 28 mL of anhydrous DMF was added. The mixture was heated to reflux for 24 h. After cooling to room temperature, the dark solution was poured into ice- water. After filtration, the yellow solid obtained was recrystalized in

dichloromethane/methanol to give (7) (5.1Og, 85.5 %). ¹H NMR (CD₂CI₂, 400 MHz, ppm) δ 8.61(d, 2H, J= 9.2 Hz), 8.34 (d, 2H, J=1.6 Hz ), 8.18 (d, 4H, J= 8.0 Hz), 8.02 (d, 2H, J= 8.8 ^x Hz), 7.80 (d, 2H, J = 8.8 Hz), 7.70 (dd, 2H, J =1.8, 8.6Hz ), 7.43(d, 8H, J = 3.6Hz), 7.30(m, 4H).

Step 2 - Synthesis of 4-[(3, 6-Di-9H-carbazol-9-yl)-9H-carbazol-9-yl]aniline (8) To a solution of 7 (3.71g, 6.0 mmol) in 250 mL of dry THF/ethanol(1 :1 ) was added

SnCI₂(5.69 g, 30.0 mmol). The mixture was heated to reflux for 24 h. The solvent was removed under reduced pressure then the residue was neutralized slowly with cool 40 wt% NaOH. After the mixture became alkaline, 300 mL toluene was added with stirring. The solid was removed by filtration and the aqueous layer of the filtrate was extracted with toluene twice (150 mL each time). The combined organic layer was washed with brine and dried over sodium sulfate. After the solvent was removed, off-white solid 8 was obtained (3.22 g, 91.4 %). ¹H NMR (CD₂CI₂, 400 MHz, ppm) δ 8.29(s, 2H), 8.17 (d, 4H, J=7.6 Hz ), 7.62 (d, 4H, J= 1.2 Hz), 7.48 (d, 2H, J= 8.8 Hz), 7.42 (d, 8H, J = 3.6 Hz), 7.29 (m, 4H), 6.99 (d, 2H, J = 8.8 Hz), 4.06 (s, 2H).¹³C NMR (CD₂CI₂, 100 MHz, ppm) δ 147.44, 142.28, 141.85, 130.24, 128.82, 127.50, 126.35, 126.27, 123.97, 123.48, 120.53, 120.01 , 119.93, 116.24, 111.75, 110.15. Step 3 - Synthesis of N-(4-((3,6-Di-9H-carbazol-9-yl))phenyl)-4-bromo-N-(4- bromophenyl)aniline (9) A mixture of 8 (2.24 g, 3.8 mmol) , 1-bromo-4-iodobenzene (2.80 g, 9.9 mmol), Pd(OAc)₂ (171 mg, 0.76 mmol), 1 ,1'-bis(diphenylphosphino)-ferrocene(845 mg, 1.52 mmol) and sodium terf-butoxide (1.46 g, 15.2 mmol) was purged with nitrogen and then added dry toluene (35ml_). The mixture was refluxed for 36 h in the dark and cooled to room temperature. The suspension was dispersed in 300 ml_ toluene and filtered to remove the solid. The filtrate was washed with water, brine and dried over sodium sulfate. After the solvent was removed, the residue was purified by column chromatography with n- hexane/dichloromethane (4:1 ) to give 9 as off-white solid ( 1.76 g, 51.4 %). ¹H NMR (CD₂CI₂, 400 MHz, ppm) δ 8.32(s, 2H), 8.18 (d, 4H, J=8.0 Hz ), 7.73 (d, 2H, J= 8.4 Hz), 7.63-7.67 (m, 4H), 7.48 (d, 4H, J = 8.8 Hz), 7.42 (d, 8H, J = 4.0 Hz), 7.38 (d, 2H, J = 8.8 Hz), 7.28-7.33 (m, 4H), 7.13(d, 4H, J = 8.8 Hz). ¹³C NMR (CD₂CI₂, 100 MHz, ppm) δ

146.83, 146.28, 141.84, 140.89, 132.62, 131.78, 130.29, 128.17, 126.16, 126.11 , 125.89, 124.83, 123.93, 123.13, 120.17, 119.68, 119.67, 116.28, 111.36, 109.70.

Example 4 - Synthesis of PCSF

To a 25 mL round bottom flask charged with 9,9-dihexylfluorene-2,7- bis(trimethyleneborate) (10) (200.9 mg, 0.40 mmol), 4,4'-(2',7^I-dibromo-9,9¹- spirobi[fluorene]-2,7-diyl)dibenzonitrile (3) (270.5 mg, 0.40 mmol), potassium carbonate (198.1 mg, 1.45 mmol) and tetrabutylammonium bromide (30.72.mg, 0.10 mmol) was added tetrakis(triphenylphosphine)palladium(0) (1.2 mg) in a glove-box. Degassed toluene (3.5 mL) and water (0.8 mL) was added into the mixture by syringe. After heating the mixture at 83^°C under nitrogen atmosphere for 42 h, excess phenylboronic acid and bromobenzene were added as end-capping reagents. The mixture was extracted with chloroform three times, and the combined organic extracts were washed with water, brine and dried over sodium sulfate. The salt was filtered off and the filtrate was concentrated into a small amount. The polymer solution was added dropwise into stirred methanol. After filtration, the collected solid was purified by re-precipitating into methanol and then Soxhlet extraction with acetone. The polymer was then dried under vacuum to give 283.0 mg of light yellow solid with a yield of 83.3 %. GPC (THF) M_n = 4.6 kDa, M_w = 5.9 kDa, PDI = 1.28. ¹H NMR (CD₂CI₂, 400 MHz, ppm) δ 8.01-8.10 (m, 4H), 7.35-7.76 (m, 18H), 7.05-7.15 (m, 4H), 1.92 (br, 4H), 0.92-0.99 (m, 12H), 0.52-0.71 (m, 10H).

Example 5 - Synthesis of PCPC4a

To a 25 mL round bottom flask charged with 9,9-dihexylfluorene-2,7- bis(trimethyleneborate) (10) (226.0 mg, 0.45 mmol), 4,4¹-(2¹,7'-dibromo-9,9¹- spirobi[fluorene]-2,7-diyl)dibenzonitrile (3) (202.9 mg, 0.30 mmol), potassium carbonate (222.8 mg, 1.63 mmol), N-(4-(9H- carbazol-9-yl)phenyl)-4-bromo-N-(4- bromophenyl)aniline (5) (85.2 mg, 0.15 mmol) and tetrabutylammonium bromide (34.5 mg, 0.11 mmol) was added tetrakis(triphenylphosphine)palladium(0) (1.5 mg) in glove- box. Degassed toluene (3.6 mL) and water (0.8 mL) was added into the mixture by syringe. After heating the mixture at 80^°C under nitrogen atmosphere for 42 h, excess phenylboronic acid and bromobenzene were added as end-capping reagents. The mixture was extracted with chloroform three times, and the combined organic extracts were washed with water, brine and dried over sodium sulfate. The salt was filtered off and the filtrate was concentrated into a small amount. The polymer solution was added dropwise into stirred methanol. After filtration, the collected solid was purified by re-precipitating into methanol and then Soxhlet extraction with acetone. The polymer was then dried under vacuum to give 299.1 mg of light yellow solid with a yield of 81.7 %. GPC (THF) M_n = 12.9 kDa, M_w = 22.8 kDa, PDI = 1.77. ¹H NMR (CD₂CI₂, 400 MHz, ppm) δ 8.17 (d, 2H, J = 6.8 Hz), 8.02-8.12 (m, 8H), 7.30-7.81 (m, 60H), 7.05-7.16 (m, 8H), 1.92-2.09 (m, 12H), 0.93- 1.00 (m, 36H), 0.51-0.77 (m, 30H). Example 6 - Synthesis of PCPC4

To a 25 mL round bottom flask charged with 9,9-dihexylfluorene-2,7- bis(trimethyleneborate) (10) (502.3 mg, 1.00 mmol), 4,4'-(2^I,7¹-dibromo-9,9¹- spirobi[fluorene]-2,7-diyl)dibenzonitrile (3) (338.2 mg, 0.50 mmol), potassium carbonate (495.2 mg, 3.62 mmol), N-(4-(9H- carbazol-9-yl)phenyl)-4-bromo-N-(4- bromophenyl)aniline (5) (284.1 mg, 0.50 mmol) and tetrabutylammonium bromide

(76.7mg, 0.24 mmol) was added tetrakis(triphenylphosphine)palladium(0) (3 mg) in glove- box. Degassed toluene (8 mL) and water (1.8 mL) was added into the mixture by syringe. After heating the mixture at 83°C under nitrogen atmosphere for 42 h, excess

phenylboronic acid and bromobenzene were added as end-capping reagents. The mixture was extracted with chloroform for three times, and the combined organic extracts were washed with water, brine and dried over sodium sulfate. The salt was filtered off and the filtrate was concentrated into a small amount. The polymer solution was added dropwise into stirred methanol. After filtration, the collected solid was purified by re-precipitating into methanol and then Soxhlet extraction with acetone. The polymer was then dried under vacuum to give 435.4 mg of light yellow solid with a yield of 54.7 %. GPC(THF) Mn = 16.5 kDa, Mw = 26.0 kDa, PDI = 1.57. ¹H NMR (CD₂CI₂, 400 MHz, ppm) δ 8.17(d, 2H, 6.8 Hz), 8.02-8.12(m, 4H), 7.31-7.82(m, 42H), 7.08-7.16(m, 4H), 1.94-2.10(m, 8H), 0.93-1.10(m, 24H), 0.52-0.77(m, 20H). Example 7 - Synthesis of PCPC4b

To a 25 ml. round bottom flask charged with 9,9-dihexylfluorene-2,7- bis(trimethyleneborate) (10) (226.0 mg, 0.45 mmol), 4,4¹-(2',7'-dibromo-9,9^I- spirobi[fluorene]-2,7-diyl)dibenzonitrile (3) (101.5 mg, 0.15 mmol), potassium carbonate (222.8 mg, 1.63 mmol), N-(4-(9H- carbazol-9-yl)phenyl)-4-bromo-N-(4- bromophenyl)aniline (5) (170.5 mg, 0.30 mmol) and tetrabutylammonium bromide (34.5 mg, 0.11 mmol) was added tetrakis(triphenylphosphine)palladium(0) (1.5 mg) in glove- box. Degassed toluene (3.6 ml_) and water (0.8 mL) was added into the mixture by syringe. After heating the mixture at 83^°C under nitrogen atmosphere for 42 h, excess phenylboronic acid and bromobenzene were added as end-capping reagents. The mixture was extracted with chloroform for three times, and the combined organic extracts were washed with water, brine and dried over sodium sulfate. The salt was filtered off and the filtrate was concentrated into a small amount. The polymer solution was added dropwise into stirred methanol. After filtration, the collected solid was purified by re-precipitating into methanol and then Soxhlet extraction with acetone. The polymer was then dried under vacuum to give 214.9 mg of light yellow solid with a yield of 62.2 %. GPC (THF) M_n = 14.5 kDa, M_w = 29.3 kDa, PDI = 2.02. ¹H NMR (CD₂CI₂, 400 MHz, ppm) δ 8.17 (d, 4H, J = 7.2 Hz), 8.02-8.12 (m, 4H), 7.31-7.83 (m, 66H), 7.07-7.16 (m, 4H), 1.91-2.10 (m, 12H), 0.92- 1.10 (m, 36H), 0.51-0.77 (m, 30H).

Example 8 - Synthesis of PCPF

To a 25 mL round bottom flask charged with 9,9-dihexylfluorene-2,7- bis(trimethyleneborate) (10) (301.4 mg, 0.60 mmol), potassium carbonate (297.12 mg, 2.17 mmol), N-(4-(9H- carbazol-9-yl)phenyl)-4-bromo-N-(4-bromophenyl)aniline (5) (340.98 mg, 0.60 mmol) and tetrabutylammonium bromide (46.0 mg, 0.14 mmol) was added tetrakis(triphenylphosphine)palladium(0) (1.8 mg) in glove-box. Degassed toluene (4.8 mL) and water (1.1 mL) was added into the mixture by syringe. After heating the mixture at 83^°C under nitrogen atmosphere for 42 h, excess phenylboronic acid and bromobenzene were added as end-capping reagents. The mixture was extracted with chloroform for three times, and the combined organic extracts were washed with water, brine and dried over sodium sulfate. The salt was filtered off and the filtrate was concentrated into a small amount. The polymer solution was added dropwise into stirred methanol. After filtration, the collected solid was purified by re-precipitating into methanol and then Soxhlet extraction with acetone. The polymer was then dried under vacuum to give 284.0 mg of light yellow solid with a yield of 63.9 %. GPC (THF) M_n = 17.6 kDa, M_w = 45.0 kDa, PDI = 2.56. ¹H NMR (CD₂CI₂, 400 MHz, ppm) <J 8.17 (d, 2H, J = 7.2 Hz), 7.30- 7.82 (m, 24H), 2.10 (br, 4H), 1.10 (br, 12H), 0.78 (br, 10H).

Example 9 - Synthesis of PTCC4a

To a 25 mL round bottom flask charged with 9,9-dihexylfluorene-2,7- bis(trimethyleneborate) (10) (226.0 mg, 0.45 mmol), 4,4'-(2^I,7¹-dibromo-9,9¹- spirobi[fluorene]-2,7-diyl)dibenzonitrile (3) (202.9 mg, 0.30 mmol), potassium carbonate (222.8 mg, 1.63 mmol), N-(4-((3,6-Di-9H-carbazol-9-yl))phenyl)-4-bromo-N-(4- bromophenyl)aniline (9) (134.8 mg, 0.15 mmol) and tetrabutylammonium bromide (34.5 mg, 0.11 mmol) was added tetrakis(triphenylphosphine)palladium(0) (1.5 mg) in glove- box. Degassed toluene (3.6 mL) and water (0.8 mL) was added into the mixture by syringe. After heating the mixture at 83^°C under nitrogen atmosphere for 42 h, excess phenylboronic acid and bromobenzene were added as end-capping reagents. The mixture was extracted with chloroform for three times, and the combined organic extracts were washed with water, brine and dried over sodium sulfate. The salt was filtered off and the filtrate was concentrated into a small amount. The polymer solution was added dropwise into stirred methanol. After filtration, the collected solid was purified by re-precipitating into methanol and then Soxhlet extraction with acetone. The polymer was then dried under vacuum to give pale yellow solid with a yield of 75.6 %. GPC(THF) Mn = 11.0 kDa, Mw = 16.5 kDa, PDI = 1.50. ¹H NMR (CD₂CI₂, 400 MHz, ppm) δ 8.32(s, 2H), 8.18 (d, 4H, J=7.6 Hz ), 8.02-8.12 (m, 8H), 7.26-7.76 (m, 70H), 7.07-7.16 (m, 8H), 1.92-2.10(m, 12H), 0.92- 1.05 (m, 36H), 0.63-0.77 (m, 30H). Example 10 - Synthesis of PTCC4 To a 25 mL round bottom flask charged with 9,9-dihexylfluorene-2,7- bis(trimethyleneborate) (10) (401.8 mg, 0.80 mmol), 4,4¹-(2',7^I-dibromo-9,9¹- spirobi[fluorene]-2,7-diyl)dibenzonitrile (3) (270.6 mg, 0.40 mmol), potassium carbonate (396.2 mg, 2.90 mmol), N-(4-((3,6-Di-9H-carbazol-9-yl))phenyl)-4-bromo-N-(4- bromophenyl)aniline (9) (359.5 mg, 0.40 mmol) and tetrabutylammonium bromide

(61.4mg, 0.19 mmol) was added tetrakis(triphenylphosphine)palladium(0) (2 mg) in glove- box. Degassed toluene (6.4 mL) and water (1.5 mL) was added into the mixture by syringe. After heating the mixture at 83^°C under nitrogen atmosphere for 42 h, excess phenylboronic acid and bromobenzene were added as end-capping reagents. The mixture was extracted with chloroform for three times, and the combined organic extracts were washed with water, brine and dried over sodium sulfate. The salt was filtered off and the filtrate was concentrated into a small amount. The polymer solution was added dropwise into stirred methanol. After filtration, the collected solid was purified by re-precipitating into methanol and then Soxhlet extraction with acetone. The polymer was then dried under vacuum to give 557.2 mg of pale yellow solid with a yield of 72.4%. GPC(THF) Mn = 24.1 kDa, Mw = 40.5 kDa, PDI = 1.68. ¹H NMR (CD₂CI₂, 400 MHz, ppm) δ 8.32(s, 2H), 8.18 (d, 4H, J=7.6 Hz ), 8.03-8.09(m, 4H), 7.29-7.74(m, 52H), 7.09-7.16(m, 4H), 1.93-2.01(m, 8H), 0.92-1.09(m, 24H), 0.52-0.77(m, 20H). Example 11 - Synthesis of PTCC4b

To a 25 mL round bottom flask charged with 9,9-dihexylfluorene-2,7- bis(trimethyleneborate) (10) (226.0 mg, 0.45 mmol), 4,4'-(2¹,7'-dibromo-9,9'- spirobi[fluorene]-2,7-diyl)dibenzonitrile (3) (101.5 mg, 0.15 mmol), potassium carbonate (222.8 mg, 1.63 mmol), N-(4-((3,6-Di-9H-carbazol-9-yl))phenyl)-4-bromo-N-(4- bromophenyl)aniline (9) (269.6 mg, 0.30 mmol) and tetrabutylammonium bromide (34.5 mg, 0.11 mmol) was added tetrakis(triphenylphosphine)palladium(0) (1.5 mg) in glove- box. Degassed toluene (3.6 mL) and water (0.8 mL) was added into the mixture by syringe. After heating the mixture at 83^°C under nitrogen atmosphere for 42 h, excess phenylboronic acid and bromobenzene were added as end-capping reagents. The mixture was extracted with chloroform for three times, and the combined organic extracts were washed with water, brine and dried over sodium sulfate. The salt was filtered off and the filtrate was concentrated into a small amount. The polymer solution was added dropwise into stirred methanol. After filtration, the collected solid was purified by reprecipitating into methanol and then Soxhlet extraction with acetone. The polymer was then dried under vacuum to give a pale yellow solid with a yield of 75.7 %. GPC(THF) Mn = 15.6 kDa, Mw = 25.0 kDa, PDI = 1.60. ¹H NMR (CD₂CI₂, 400 MHz, ppm) δ 8.32(s, 4H), 8.18 (d, 8H, J=7.6 Hz ), 8.05-8.11 (m, 4H), 7.306-7.82 (m, 86H), 7.07-7.16 (m, 4H), 2.01-2.10(d, br, 12H), 0.92-1.10 (m, 36H), 0.53-0.77 (m, 30H). Example 12 - Synthesis of PTCPF

To a 25 ml. round bottom flask charged with 9,9-dihexylfluorene-2,7- bis(trimethyleneborate) (10) (200.9 mg, 0.40 mmol), potassium carbonate (198.1 mg, 1.45 mmol), N-(4-((3,6-Di-9H-carbazol-9-yl))phenyl)-4-bromo-N-(4-bromophenyl)aniline (9) (359.5 mg, 0.40 mmol) and tetrabutylammonium bromide (30.72 mg, 0.10 mmol) was added tetrakis(triphenylphosphine)palladium(0) (1.3 mg) in glove-box. Degassed toluene (3.2 mL) and water (0.7 mL) was added into the mixture by syringe. After heating the mixture at 83°C under nitrogen atmosphere for 42 h, excess phenylboronic acid and bromobenzene were added as end-capping reagents. The mixture was extracted with chloroform for three times, and the combined organic extracts were washed with water, brine and dried over sodium sulfate. The salt was filtered off and the filtrate was concentrated into a small amount. The polymer solution was added dropwise into stirred methanol. After filtration, the collected solid was purified by re-precipitating into methanol and then Soxhlet extraction with acetone. The polymer was then dried under vacuum to give a pale yellow solid with a yield of 41.7%. GPC(THF) Mn = 17.1 kDa, Mw = 27.4 kDa, PDI = 1.60. ¹H NMR (CD₂CI₂, 400 MHz, ppm) δ 8.31 (s, 2H), 8.17 (d, br, 4H), 7.29-7.80 (m, 34H), 2.10(d, br, 4H), 1.10 (br, 12H), 0.77 (br, 10H).

Device fabrication and measurement

Polymer OLED devices were fabricated in the following configuration:

ITO/PEDOT:PSS/emissive layer/CsF/Ca/AI. All devices were prepared on ITO. A layer of 50nm thick polyethylenedioxythiophene-polystyrenesulfonate (PEDOT:PSS Bayer, Germany) was spin-coated onto the precleaned ITO substrates and then baked at 120 ⁰C for 30 minutes to extract residual water. Next, a mixture of 70 wt% polymer and 30 wt% PBD, dissolved in chloroform at concentration of 1%, was spin-coated at 1500 rpm onto PEDOT as the emissive layer. The polymer of the emissive layer in each case is described below in Examples 13 to 21. The samples were annealed at 120 ⁰C for 30 minutes to remove residual solvent. The thickness of the emissive layer was about 80 nm. Finally, a 1 nm thick CsF buffer layer and a cathode of bilayer Ca (20 nm)/AI (100 nm) were then thermally evaporated at a chamber base pressure of <10^"4 Pa. The device area was 16 mm², which is determined by widths of ITO and Ca/AI electrodes. The evaporated layer thicknesses were controlled using a crystal thickness monitor and a step profiler (Dektak 6M stylus profiler, Veeco) was used to determine the thickness of the spin coated films.

Figure 3 shows a schematic diagram of the OLED device with configuration of

ITO/PEDOTiPSS/PolymeπPBD/CsF/Ca/AI.

The steady-state current-brightness-voltage characteristics were recorded using a computer-controlled source meter (Keithley 2400) with a calibrated Si photodiode. The EL spectra were measured by a PR650 SpectraScan spectrophotometer. All data are obtained at room temperature.

Example 13 -control device

A device with the configuration of ITO/PEDOT/PCSF:PBD (7:3)/CsF/Ca/AI using

PCPC4:PBD (7:3) as the emissive layer emits greenish blue light with maximum emissive wavelength of 456 nm. Turn-on voltage is 3.5 V. The maximum brightness is 2530 cd/m² (at 8.7 V); maximum current efficiency is 0.98 cd/A (at 5.1 V); current efficiency at 100 cd/m² is 0.91 cd/A (at 4.3 V).

Example 14 -control device

A device with the configuration of ITO/PEDOT/PCPF:PBD (7:3)/CsF/Ca/AI using

PCPC4:PBD (7:3) as the emissive layer emits greenish blue light with maximum emissive wavelength of 464 nm. Turn-on voltage is 4.7 V. The maximum brightness is 2466 cd/m² (at 10.9 V); maximum current efficiency is 0.56 cd/A (at 8.1 V); current efficiency at 100 cd/m² is 0.39 cd/A (at 6.5 V). Example 15 -control device

A device with the configuration of ITO/PEDOT/PTCPF:PBD (7:3)/CsF/Ca/AI using PCPC4:PBD (7:3) as the emissive layer emits greenish blue light with maximum emissive wavelength of 460 nm. Turn-on voltage is 3.7 V. The maximum brightness is 3571 cd/m² (at 10.1 V); maximum current efficiency is 0.80 cd/A (at 6.5 V); current efficiency at 100 cd/m² is 0.72 cd/A (at 4.9 V). Example 16 - working product A

A device with the configuration of ITO/PEDOT/PCPC4a:PBD (7:3)/CsF/Ca/AI using PCPC4:PBD (7:3) as the emissive layer emits greenish blue light with maximum emissive wavelength of 484 nm. Turn-on voltage is 3.2 V. The maximum brightness is 5306 cd/m² (at 10.3 V); maximum current efficiency is 1.64 cd/A (at 5.3 V); current efficiency at 100 cd/m² is 1.52 cd/A (at 4.3 V). Example 17- working product B

A device with the configuration of ITO/PEDOT/PCPC4:PBD (7:3)/CsF/Ca/AI using PCPC4:PBD (7:3) as the emissive layer emits greenish blue light with maximum emissive wavelength of 484 nm. Turn-on voltage is 3.1 V. The maximum brightness is 6369 cd/m² (at 10.9 V); maximum current efficiency is 1.97 cd/A (at 5.3 V); current efficiency at 100 cd/m² is 1.86 cd/A (at 4.3 V).

Example 18 - working product C A device with the configuration of ITO/PEDOT/PCPC4b:PBD (7:3)/CsF/Ca/AI using

PCPC4:PBD (7:3) as the emissive layer emits greenish blue light with maximum emissive wavelength of 472 nm. Turn-on voltage is 3.2 V. The maximum brightness is 4072 cd/m² (at 10.3 V); maximum current efficiency is 1.16 cd/A (at 5.3 V); current efficiency at 100 cd/m² is 1.10 cd/A (at 4.3 V).

Example 19 - working product D

A device with the configuration of ITO/PEDOT/PTCC4a:PBD (7:3)/CsF/Ca/AI using PCPC4:PBD (7:3) as the emissive layer emits greenish blue light with maximum emissive wavelength of 476 nm. Turn-on voltage is 4.1 V. The maximum brightness is 5386cd/m² (at 10.3 V); maximum current efficiency is 1.77 cd/A (at 6.7 V); current efficiency at 100 cd/m² is 1.26 cd/A (at 5.3 V).

Example 20 - working product E A device with the configuration of ITO/PEDOT/PTCC4:PBD (7:3)/CsF/Ca/AI using PCPC4:PBD (7:3) as the emissive layer emits greenish blue light with maximum emissive wavelength of 460 nm. Turn-on voltage is 3.0 V. The maximum brightness is 7257 cd/m² (at 7.9 V); maximum current efficiency is 1.76 cd/A (at 4.5 V); current efficiency at 100 cd/m² is 1.50 cd/A (at 3.8 V).

Example 21 - working product F

A device with the configuration of ITO/PEDOT/PTCC4b:PBD (7:3)/CsF/Ca/AI using PCPC4:PBD (7:3) as the emissive layer emits greenish blue light with maximum emissive wavelength of 468 nm. Turn-on voltage is 3.6 V. The maximum brightness is 3157cd/m² (at 10.9 V); maximum current efficiency is 1.02 cd/A (at 5.3 V); current efficiency at 100 cd/m² is 0.97 cd/A (at 4.9 V). Results and analysis

The results of the TGA analysis of PCPC4 and PTCC4 are set out in the plot shown in Figure 4. The onset degradation temperature for PCPC4 and PTCC4 are 433 ⁰C and 422⁰C, respectively, which showed very good thermal stability.

The results of the DSC analysis of PCPC4 and PTCC4 are set out in the plot shown in Figure 5.

The glass transition temperature (Tg) for PCPC4 and PTCC4 are 238⁰C and 273⁰C, respectively. This high Tg contributed to good OLED device operation.

The UV-vis absorption and photoluminescence (PL) spectra of PCPC4 and PTCC4 in toluene are set out in Figure 6.

The UV-vis absorption and photoluminescence (PL) spectra of PCPC4 and PTCC4 as thin films are set out in Figure 7. (The film thickness is ~100nm.) The electroluminescence (EL) spectrum of PCPC4 is shown in Figure 8. The I-V-L characteristics of PCPC4 are plotted in Figure 8A. The current efficiency of PCPC4 is plotted in Figure 9B.

The electroluminescence (EL) spectrum of PTCC4 is shown in Figure 10.

The I-V-L characteristics of PTCC4 are plotted in Figure 11 A. The current efficiency of PTCC4 is plotted in Figure 11 B.

Claims

1. A compound having (1 ) a backbone portion, which backbone portion includes a hole transporting portion comprising a triarylamine group; (2) a side chain portion attached to the backbone portion, which side chain portion includes an electron transporting portion comprising an electron deficient aryl group; and (3) a spacer portion located between the hole transporting portion and the electron transporting portion.

2. A compound according to claim 1 , wherein the compound comprises the structure according to formula I:

(I)

wherein:

-A- or -A-B- comprises a triarylamine and is optionally substituted;

n is independently 1 to 200.

3. A compound according to claim 1 or claim 2, wherein the compound comprises the structure according to formula II:

(H) wherein:

each of Ar₁, Ar₂, Ar_4a, Ar_4b, Ar₅, Ar_7a and Ar_7b is independently arylene, and is optionally substituted; Ar₃ is independently aryl, aryl vinylene or aryl ethynylene, and is optionally substituted;

X is independently alkylene, alkenylene, -O-, -OC(O)-, -C(O)O-, -C(0)NR_A-, or - NR_AC(O)-, wherein each R_A, if present, is independently H, alkyl or aryl and is optionally substituted;

e is independently 0 or 1 ;

each of m, s, v and w is independently 1 to 20;

each of I, p, r and t is independently 0 to 20;

z is independently 0 to 3; and

n is independently 1 to 200;

and wherein:

at least one of p and r≠ 0

and wherein:

when n≠ 1 at least one of I and t≠ 0.

4. A compound according to claim 3, wherein the compound comprises the structure according to formula III:

(III)

wherein

Ar₁, Ar₂, Ar₃, Ar₄₃, Ar_4b, Ar₅, Ar₆, Ar₇₃, Ar_7b and X are as defined above; and e, I, m, p, r, s, t, v, w, z and n are as defined above;

and wherein

5. , A compound according to claim 4, wherein each Ar₁ is independently C_5-5oarylene and is optionally substituted.

6. A compound according to claim 4, wherein each Ar₁ is independently phenylene, fluorenylene, carbazolylene, diarylamino, spirobifluorenylene, spirosilabifluorenylene, indenocarbazolylene, indenofluorenylene, thienylene, thienothienylene or

benzothiadiazolylene and is optionally substituted

7. A compound according to claim 6, wherein each Ar₁ is independently phenylene and is optionally substituted.

8. A compound according to any one of claims 3 to 7, wherein each Ar₂ is

independently C_5-5oarylene and is optionally substituted.

9. A compound according to claim 8, wherein each Ar₂ is independently phenylene, fluorenylene, carbazolylene, diarylamino, spirobifluorenylene, spirosilabifluorenylene, indenocarbazolylene, indenofluorenylene, thienylene, thienothienylene or

benzothiadiazolylene and is optionally substituted.

10. A compound according to claim 9, wherein each Ar₂ is independently phenylene and is optionally substituted.

11. A compound according to any one of claims 3 to 10, wherein each Ar_4a is independently C_5-5oarylene and is optionally substituted.

12. A compound according to claim 11 , wherein each Ar₄₃ is independently phenylene, fluorenylene, carbazolylene, diarylamino, spirobifluorenylene, spirosilabifluorenylene, indenocarbazolylene, indenofluorenylene, thienylene, thienothienylene or

benzothiadiazolylene and is optionally substituted.

13. A compound according to claim 12, wherein each Ar_4a is independently

fluorenylene, and is optionally substituted.

14. A compound according to claim 13, wherein each Ar_4a is independently

15. A compound according to any one of claims 3 to 14, wherein each Ar_4b is independently C_5-5oarylene and is optionally substituted.

16. A compound according to claim 15, wherein each Ar_4b is independently phenylene, fluorenylene, carbazolylene, diarylamino, spirobifluorenylene, spirosilabifluorenylene, indenocarbazolylene or indenofluorenylene, and is optionally substituted.

17. A compound according to claim 16, wherein each Ar_4b is independently

fluorenylene, and is optionally substituted.

18. A compound according to any one of claims 3 to 17, wherein each Ar₅ is independently C₅.₅₀arylene and is optionally substituted.

19. A compound according to claim 18, wherein each Ar₅ is independently phenylene, fluorenylene, carbazolylene, diarylamino, spirobifluorenylene, spirosilabifluorenylene, indenocarbazolylene, indenofluorenylene, thienylene, thienothienylene or

benzothiadiazolylene and is optionally substituted.

20. A compound according to claim 19, wherein each Ar₅ is independently

fluorenylene and is optionally substituted

21. A compound according to claim 20, wherein each Ar₅ is independently

Ar₆

22. A compound according to any one of claims 3 to 21 , wherein each Ar_7a is independently C_5-50arylene and is optionally substituted.

23. A compound according to claim 22, wherein each Ar_7a is independently phenylene, fluorenylene, carbazolylene, diarylamino, spirobifluorenylene, spirosilabifluorenylene, indenocarbazolylene, indenofluorenylene, thienylene, thienothienylene or

benzothiadiazolylene and is optionally substituted.

24. A compound according to claim 23, wherein each Ar_7a is independently

fluorenylene, and is optionally substituted.

25. A compound according to claim 24, wherein each Ar_7a is independently

26. A compound according to any one of claims 3 to 25, wherein each Ar_7b is independently C_5-5oarylene and is optionally substituted.

27. A compound according to claim 26, wherein each Ar_7b is independently phenylene, fluorenylene, carbazolylene, diarylamino, spirobifluorenylene, spirosilabifluorenylene, indenocarbazolylene or indenofluorenylene, and is optionally substituted.

28. A compound according to claim 27, wherein each Ar_7b is independently

fluorenylene, and is optionally substituted.

29. A compound according to any one of claims 3 to 28, wherein Ar₄₃, Ar_4b, Ar_7a and Ar_7b, if present, are the same.

30. A compound according to any one of claims 3 to 29, wherein each Ar₃ is independently C_5-5Oaryl, C_5-5oaryl vinylene or C_5-5oaryl ethynylene and is optionally substituted.

31. A compound according to claim 30, wherein each Ar₃ is independently phenylene, fluorenylene, carbazolylene, diarylamino, spirobifluorenylene, spirosilabifluorenylene, indenocarbazolylene, indenofluorenylene, thienylene, thienothienylene or

benzothiadiazolylene and is optionally substituted.

32. A compound according to claim 31 , wherein each Ar₃ is independently phenyl and is optionally substituted.

33. A compound according to claim 32, wherein each Ar₃ is independently selected from

34. A compound according to any one of claims 3 to 33, wherein each Ar₆ is independently electron deficient C_5-4Oaryl, C_5-4Oaryl vinylene or C_5-40aryl ethynylene, and is optionally substituted with an electron withdrawing group, and is optionally further substituted.

35. A compound according to claim 34, wherein each Ar₆ is independently fluorenyl subtituted with an electron withdrawing group.

36. A compound according to claim 35, wherein each Ar₆ is independently

wherein R_EW is an electron withdrawing group.

37. A compound according to claim 36, wherein each R_EW is independently selected from halo, -CN, -NO₂, -CO, thionyl, sulphonyl and perfluoroalkyl.

38. A compound according to any one of claims 4 to 37, wherein each Ar₈, if present, is independently C_5-50aryl, C_5-50aryl vinylene or C_5-50aryl ethynylene and is optionally substituted.

39. A compound according to claim 38, wherein each Ar₈, if present, is independently phenyl and is optionally substituted.

40. A compound according to any one of claims 4 to 39, wherein each Ar₉, if present, is independently C_5-5oaryl, C_5-50aryl vinylene or C_5-50aryl ethynylene and is optionally substituted.

41. A compound according to claim 40, wherein each Ar₉, if present, is independently phenyl and is optionally substituted.

42. A compound according to any one of claims 3 to 41 , wherein

each m is independently 1 to 10, preferably 1 to 5;

each s is independently 1 to 10, preferably 1 to 5;

each v is independently 1 to 5, preferably 1 to 3;

each w is independently 1 to 5, preferably 1 to 3;

each I is independently 0 to 5, preferably 0 to 3;

each p is independently 0 to 5, preferably 0 to 3;

each r is independently 0 to 5, preferably 0 to 3;

each t is independently 0 to 5, preferably 0 to 3; and

each n is independently 1 to 20, preferably 1 to 3.

43. A compound according to any one of claims 3 to 42, wherein each e is independently 1.

44. A compound according to any one of claims 3 to 43, wherein each z is independently 0.

45. A compound according to any one of claims 3 to 44, wherein one or more of Ar₁, Ar₂, Ar₃, Ar_4a, Ar_4b, Ar₅, Ar₆, Ar_7aand Ar_7b is independently substituted by C_1-2oalkyl, C_1- ₂oalkoxy or Cs-soaryl, which substituents are optionally further substituted.

46. A thin film comprising a compound according to any one of claims 1 to 45.

47. A light emitting device comprising a compound according to any one of claims 1 to 45 or a thin film according to claim 46.