Molecules

18 pages, 1288 KiB

Open AccessArticle

The Mechanism of Aniline Blue Degradation by Short-Chain Dehydrogenase (SDRz) in Comamonas testosteroni

by Chuanzhi Zhang, Yong Huang, Jiaxin He, Lei He, Jinyuan Zhang, Lijing Yu, Elshan Musazade, Edmund Maser, Guangming Xiong, Miao Xu and Liquan Guo

Molecules 2024, 29(22), 5405; https://doi.org/10.3390/molecules29225405 (registering DOI) - 15 Nov 2024

Abstract

Dye wastewater pollution, particularly from persistent and toxic polycyclic organic pollutants, such as aniline blue, poses a significant environmental challenge. Aniline blue, a triphenylmethane dye widely used in the textile, leather, paper, and pharmaceutical industries, is notoriously difficult to treat owing to its [...] Read more.

Dye wastewater pollution, particularly from persistent and toxic polycyclic organic pollutants, such as aniline blue, poses a significant environmental challenge. Aniline blue, a triphenylmethane dye widely used in the textile, leather, paper, and pharmaceutical industries, is notoriously difficult to treat owing to its complex structure and potential for bioaccumulation. In this study, we explored the capacity of Comamonas testosteroni (CT1) to efficiently degrade aniline blue, focusing on the underlying enzymatic mechanisms and degradation pathways. Through prokaryotic transcriptome analysis, we identified a significantly upregulated short-chain dehydrogenase (SDRz) gene (log₂FC = 2.11, p < 0.05) that plays a crucial role in the degradation process. The SDRz enzyme possessed highly conserved motifs and a typical short-chain dehydrogenase structure. Functional validation using an SDRz-knockout strain (CT-ΔSDRz) and an SDRz-expressioning strains (E-SDRz) confirmed that SDRz is essential for aniline blue degradation. The knockout strain CT-ΔSDRz exhibited a 1.27-fold reduction in the degradation efficiency, compared to CT1 strain after 12 h; while the expression strain E-SDRz showed a 1.24-fold increase compared to Escherichia coli DH5α after 12 h. Recombinant SDRz (rSDRz) was successfully produced, showing significant enzymatic activity (1.267 ± 0.04 mmol·L⁻¹·min⁻¹ protein), with kinetic parameters Vmax = 2.870 ± 0.0156 mmol·L⁻¹·min⁻¹ protein and Km = 1.805 ± 0.0128 mM·mL⁻¹. Under optimal conditions, the rSDRz achieved a degradation efficiency of 62.17% for aniline blue. Gas chromatography–mass spectrometry (GC-MS) analysis identified several intermediate metabolites in the degradation pathway, including benzeneacetaldehyde, a, a-diphenyl, 2-amino-4-methylbenzophenone, benzene, 1-dimethylamino-4-phenylmethyl, benzenesulfonic acid, methyl ester, further elucidating the biodegradation mechanism. These findings highlight SDRz as a critical enzyme in the biodegradation of aniline blue, offering valuable insights and a robust theoretical foundation for developing advanced bioremediation strategies to address dye wastewater pollution. Full article

(This article belongs to the Special Issue Innovative Materials and Methods for the Removal of Pollutants from the Environment (2nd Edition))

12 pages, 3958 KiB

Open AccessArticle

Mechanistic Insights into the Reaction of Wulfenite with Aqueous Sodium Sulfide Solution and Its Industrial Implications

by Zi Cai, Jialei Li, Shuai Ning and Ruizeng Liu

Molecules 2024, 29(22), 5404; https://doi.org/10.3390/molecules29225404 (registering DOI) - 15 Nov 2024

Abstract

The purpose of this study was to investigate the reaction mechanism of wulfenite with an aqueous sodium sulfide solution and thereby provide guidance for the sulfidization flotation and sodium sulfide leaching of wulfenite. For this purpose, dissolution/leaching behavior analysis, X-ray diffraction (XRD), Raman [...] Read more.

The purpose of this study was to investigate the reaction mechanism of wulfenite with an aqueous sodium sulfide solution and thereby provide guidance for the sulfidization flotation and sodium sulfide leaching of wulfenite. For this purpose, dissolution/leaching behavior analysis, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and field-emission scanning electron microscopy (FESEM) were performed. The dissolution/leaching analysis indicated that sodium sulfide can induce the dissolution of PbMoO₄. The XRD and Raman spectra results demonstrated that PbMoO₄ was replaced by PbS at the wulfenite–sodium sulfide solution interface, and the sulfidized wulfenite particles had a PbMoO₄/PbS core–shell structure. The XPS results also indicated the transformation of PbMoO₄ to PbS. The FESEM images showed the growth of PbS nanoparticles on the surface of wulfenite and the dissolution pits after treatment with sodium sulfide solution. These findings showed that wulfenite sulfidization proceeds through an interface-coupled dissolution–precipitation mechanism. In the presence of sodium sulfide solution, the less stable PbMoO₄ dissolves, and the more stable PbS phase precipitates, both of which are coupled at the wulfenite–sodium sulfide aqueous solution interface. Full article

(This article belongs to the Special Issue Molecular Structure of Minerals)

24 pages, 2743 KiB

Open AccessReview

Insights into SARS-CoV-2: Small-Molecule Hybrids for COVID-19 Treatment

by Maria Luisa Navacchia, Caterina Cinti, Elena Marchesi and Daniela Perrone

Molecules 2024, 29(22), 5403; https://doi.org/10.3390/molecules29225403 (registering DOI) - 15 Nov 2024

Abstract

The advantages of a treatment modality that combines two or more therapeutic agents with different mechanisms of action encourage the study of hybrid functional compounds for pharmacological applications. Molecular hybridization, resulting from a covalent combination of two or more pharmacophore units, has emerged [...] Read more.

The advantages of a treatment modality that combines two or more therapeutic agents with different mechanisms of action encourage the study of hybrid functional compounds for pharmacological applications. Molecular hybridization, resulting from a covalent combination of two or more pharmacophore units, has emerged as a promising approach to overcome several issues and has also been explored for the design of new drugs for COVID-19 treatment. In this review, we presented an overview of small-molecule hybrids from both natural products and synthetic sources reported in the literature to date with potential antiviral anti-SARS-CoV-2 activity. Full article

(This article belongs to the Special Issue Strategies in the Design and Development of Antiviral Drugs)

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Design strategy for hybrid compounds. Full article ">Figure 2
Schematic representation of the genome organization and functional domains for SARS-CoV-2. The single-stranded RNA genome of SARS-CoVs has two large genes, the ORF1a and ORF1b genes, which encode 16 non-structural proteins (nsp1–nsp16) that are highly conserved throughout coronaviruses. The structural genes encode the structural proteins, spike glycoprotein (S), envelope (E), membrane (M) and nucleocapsid (N), which are common features of all coronaviruses. Polyproteins pp1a and pp1ab embed 11 and 16 non-structural proteins (Nsps), respectively; the green and pink triangles indicate the cleavage sites of the protease PLpro and Mpro, respectively. Fifteen sites where polyproteins pp1a and pp1ab are cut by proteases are represented with arrows. PLpro cleaves at three distinct sites while Mpro cleaves at twelve distinct sites, including those for RNA-dependent RNA polymerase (RdRp) encoded by nsp12 and Helicase (Hel) encoded by nsp13. Full article ">Figure 3
Schematic representation of virus infection and replication mechanism in host cell. Full article ">Figure 4
ACE2 viral-induced dysregulation and inflammatory signaling in host cell. Full article ">Figure 5
Artemisinin-derived hybrids and selected biological data. (A): molecular structures of artemisinins; (B): dihydroatemisinin–thymoquinone hybrids; (C): molecular structures of dihydroatemisinin–quinoline hybrids; (D): molecular structures of dihydroatemisinin–ursodeoxycholic bile acid hybrids. Full article ">Figure 6
Peptidomimetic-based hybrids: molecular structures of starting frameworks; molecular structures of hybrids and selected biological data. Full article ">Figure 7
Molecular structures of 1,2,3-triazole-based hybrids and selected biological data. Full article ">Figure 8
Chemical structure of benzothiazolyl–pyridine, benzothiazolyl–coumarin, thiouracil–coumarin, thiazole–pyrazole hybrids and selected biological data. Full article ">Figure 9
Chemical structure of hybrids and selected biological data. Full article ">Figure 10
Chemical structure of hybrids and selected biological data. Full article ">

13 pages, 1282 KiB

Open AccessArticle

Molecular Mechanism: Inhibition of Fusarium oxysporum T-2 Toxin Synthesis by Surfactin in Dried Fish: Induction of Yap1 Nucleation by ROS Accumulation

by Qi Deng, Xueting Ren, Qin Hu, Yuehua Pu, Lukman Iddrisu, Anand Kumar, Meifang Hua, Jianmeng Liao, Zhijia Fang and Ravi Gooneratne

Molecules 2024, 29(22), 5402; https://doi.org/10.3390/molecules29225402 (registering DOI) - 15 Nov 2024

Abstract

(1) T-2 toxin synthesized by Fusarium oxysporum (F. oxysporum) can cause deterioration of dried fish and endanger human health. (2) The molecular mechanism by which antibacterial lipopeptides surfactin inhibited F. oxysporum growth and toxin production was elucidated by investigating the intracellular [...] Read more.

(1) T-2 toxin synthesized by Fusarium oxysporum (F. oxysporum) can cause deterioration of dried fish and endanger human health. (2) The molecular mechanism by which antibacterial lipopeptides surfactin inhibited F. oxysporum growth and toxin production was elucidated by investigating the intracellular ROS production pathway and the subcellular distribution and transcriptional activity of the transcription factor Yap1 and its regulation of Tri5 gene in F. oxysporum. (3) Surfactin caused hyphal damage and nucleic acid and protein leakage; thus, the growth of F. oxysporum was disrupted. Surfactin’s excessive accumulation of intracellular ROS triggered the translocation of transcription factor Yap1 into the nucleus, resulting in toxin cluster gene Tri5 expression inhibition, thereby blocking T-2 toxin synthesis. (4) This is a novel mechanism by which surfactin inhibits the growth and T-2 toxin synthesis of F. oxysporum from multiple aspects, including cell structural integrity and the ROS-Yap1 signaling pathway. (5) This study provides a theoretical basis for the application of surfactin in the antifungal control of aquatic dry products. Full article

(This article belongs to the Special Issue Advancing Food Safety: Chemistry in Food Microbiology Control)

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Full article ">Figure 1
Inhibitory effect of surfactin on the growth phenotype of F. oxysporum. (A) illustrates the impact of varying surfactin concentrations on the colony diameter of F. oxysporum Fo17 on PDA plates following a 7-day incubation period. The inhibitory effect of surfactin on F. oxysporum spore production (B), biomass (C), and hyphal growth (D). In (A), the different letters represent significant differences between treatments. Full article ">Figure 2
Effect of surfactin on the F. oxysporum (Fo17) hyphal structure. (A1–C1) show the light microscope morphology of Fo17 hyphae in the presence of 0, 0.5, and 1.0 mg/mL surfactin. (A2–C2) show scanning electron microscopic changes of Fo17 hyphae at 0, 0.5, and 1.0 mg/mL surfactin, respectively. Full article ">Figure 3
Effect of surfactin on F. oxysporum nucleic acid and protein release levels (***: p < 0.001). Full article ">Figure 4
Inhibition of surfactin induced ROS accumulation (A) and T-2 toxin synthesis (B) in F. oxysporum by ROS inhibitors (**: p < 0.01; ***: p < 0.001). Different letters represent significant differences between treatments. Full article ">Figure 5
Amplified genes in Yap1 knockout transformants. (A) shows the amplified genes HYG: M, DNA Markers; 1. Markers No. 1; 2. Invertor #2; 3. Invertor #3; 4. Invertor #4. (B) shows the amplified genes Yap1-5′-YY and Yap1-3′-YG: M, DNA markers; 1. Invertor #1 mycelial DNA was used as a template to amplify the Yap1-5′-HY and Yap1-3′-YG in Yap1 knockdown transformants HY and Yap1-3′-YG: M is DNA Markers; 1. Invertor #1 mycelial DNA was used as a template to amplify Yap1-A1HY; 2. Invertor #1 mycelial DNA was used as template to amplify Yap1-A4YG). Full article ">Figure 6
Colony and mycelial morphology of ∆Yap1 cultured for 7 d in solid media. (A) = PDA; (B) = GYM; (C) = CMC; (1–3) show the structure of mycelium under a microscope (40×). Full article ">Figure 7
T-2 toxin synthesis and Tri5 expression in Fo17 and ∆Yap1 strains of Fusarium oxysporum (*: p < 0.05). Full article ">Figure 8
PCR validation of the backfill primers. M: 250 bp DNA ladder; 1: back-transformant Y1, 2: back-transformant Y2; 3: back-transformant Y3; 4: back-transformant G1; 5: back-transformant G2; 6: back-transformant G3; 7: 1300-neo-Yap1 recombinant plasmid; 8: F. oxysporum (Yap1-deficient). Full article ">Figure 9
Effect of surfactin on the subcellular distribution of Fo17 Yap1. Full article ">

15 pages, 4421 KiB

Open AccessReview

Unusual Lignocellulosic Bioresins: Adhesives and Coatings for Metals and Glass

by Antonio Pizzi

Molecules 2024, 29(22), 5401; https://doi.org/10.3390/molecules29225401 (registering DOI) - 15 Nov 2024

Abstract

This minireview presents some unusual but encouraging examples of lignocellulosic-based adhesives and coatings used for metals, glass, and some other difficult-to-adhere materials. The reactions and applications presented are as follows. (i) The reactions of tannins and wood lignin with phosphate salts, in particular [...] Read more.

This minireview presents some unusual but encouraging examples of lignocellulosic-based adhesives and coatings used for metals, glass, and some other difficult-to-adhere materials. The reactions and applications presented are as follows. (i) The reactions of tannins and wood lignin with phosphate salts, in particular triethylphosphate, to adhere and join steel and aluminum to Teflon, in particular for non-stick frying pans. These adhesive coatings have been shown to sustain the relevant factory industrial test of 410 °C for 11 min and, moreover, to present a 50% material loss even at 900 °C for 5 min. (ii) Non-isocyanate polyurethanes (NIPU) based on glucose and sucrose as coatings of steel and glass. These were obtained by the carbonation of carbohydrates through reaction with the inexpensive dimethyl carbonate followed by reaction with a diamine; all materials used were bio-sourced. Lastly, (iii) the use of citric acid-based adhesive coupled with any hydroxyl groups carrying material for coating metals is also described. These three approaches give a clear indication of the possibilities and capabilities of biomaterials in this field. All these are presented and discussed. Full article

(This article belongs to the Special Issue Advances in Polymer Materials Based on Lignocellulosic Biomass)

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22 pages, 703 KiB

Open AccessArticle

Quantitative Analysis of Lactobionic Acid in Bioreactor Cultures and Selected Biological Activities

by Kamila Goderska, Wojciech Juzwa and Tomasz M. Karpiński

Molecules 2024, 29(22), 5400; https://doi.org/10.3390/molecules29225400 (registering DOI) - 15 Nov 2024

Abstract

The aim of this study was to quantitatively analyse lactobionic acid obtained from bioreactor cultures using whey as a liquid medium with bacteria of the Pseudomonas taetrolens species. The most important culture parameters affecting the production of the acid are indicated and evaluated. [...] Read more.

The aim of this study was to quantitatively analyse lactobionic acid obtained from bioreactor cultures using whey as a liquid medium with bacteria of the Pseudomonas taetrolens species. The most important culture parameters affecting the production of the acid are indicated and evaluated. The highest lactobionic acid yield was 37.42 g/L, selecting the appropriate strain (Pseudomonas taetrolens 4′) and environmental conditions (2% lactose concentration in the bioreactor). The amount of lactose and lactobionic acid was determined by high-performance liquid chromatography. Microorganism analysis was also carried out using a flow cytometer with imaging to study the metabolic activity of microorganisms during lactobionic acid production. In addition, during the study, Bifidobacteria were microencapsulated with lactobionic acid and their survival was evaluated in an in vitro model of the gastrointestinal tract, checking the prebiotic properties of the acid. The highest number of viable cells in the microcapsules after digestion was obtained using the Bifidobacterium bifidum strain DSM 20082. The antagonistic activity of lactobionic acid was also analysed. Full article

(This article belongs to the Section Organic Chemistry)

18 pages, 987 KiB

Open AccessArticle

Non-Invasive Monitoring of Corticosterone Levels in Mouse Urine with Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry

by Laura Howe-Wittek, Paul Kroschk, Kai Nieschalke, Harshadrai M. Rawel, Stephanie Krämer and Jens Raila

Molecules 2024, 29(22), 5399; https://doi.org/10.3390/molecules29225399 (registering DOI) - 15 Nov 2024

Abstract

An innovative method for the quantification of corticosterone in the urine of C57BL/6J mice by liquid chromatography-electrospray ionization-tandem mass spectrometry was developed. Unconjugated and glucuronidated corticosterone was detected in the urine samples using enzymatic hydrolysis following liquid–liquid extraction. After optimization of the extraction [...] Read more.

An innovative method for the quantification of corticosterone in the urine of C57BL/6J mice by liquid chromatography-electrospray ionization-tandem mass spectrometry was developed. Unconjugated and glucuronidated corticosterone was detected in the urine samples using enzymatic hydrolysis following liquid–liquid extraction. After optimization of the extraction protocol and LC-MS/MS parameters, we performed a validation study using a representative urine pool of C57BL/6J and Naval Medical Research Institute mice. The method shows good linearity (1–5000 fmol/µL) and the calculated limit of quantification amounts to 0.823 fmol/µL. Both intra-day and inter-day variation was ≤10%, while their recoveries amounted to 90.4–110.6% and 99.8%, respectively. Twenty-four hour urine collection of C57BL/6J mice restrained in two different metabolic cage types for two times was used to test the validated method. To control the hydration level of mice, the corticosterone concentration in their urine was normalized to urinary creatinine concentration. Our LC-MS/MS method represents a highly specific analytical tool for the quantification of corticosterone levels in urine samples, assisting in non-invasive monitoring of acute stress levels in laboratory mice. Full article

11 pages, 5038 KiB

Open AccessArticle

An Efficient Method for the Selective Syntheses of Sodium Telluride and Symmetrical Diorganyl Tellurides and the Investigation of Reaction Pathways

by Chorong Kim, Yoo Jin Lim, Ye Eun Kim, Akula S. N. Murthy, Hyunsung Cho, Hyejeong Lee, Myung-Sook Park and Sang Hyup Lee

Molecules 2024, 29(22), 5398; https://doi.org/10.3390/molecules29225398 (registering DOI) - 15 Nov 2024

Abstract

Studies on organotellurium compounds have not been extensively conducted due to a lack of tolerable synthetic methods, difficult isolation processes, and their chemical instabilities. Overcoming these hurdles, we developed an efficient and mild method for the selective synthesis of symmetrical diorganyl tellurides 1 [...] Read more.

Studies on organotellurium compounds have not been extensively conducted due to a lack of tolerable synthetic methods, difficult isolation processes, and their chemical instabilities. Overcoming these hurdles, we developed an efficient and mild method for the selective synthesis of symmetrical diorganyl tellurides 1, a representative class of organotellurium compounds, using a proper reducing reagent. The reaction condition was optimized for the selective formation of 1 by forming the telluride dianion (Te²⁻) using a reducing reagent, sodium borohydride (NaBH₄), and then followed by the addition of organyl halides. The optimized reaction condition was as follows: (1) Te (1.0 eq), NaBH₄ (2.5 eq) in DMF for 1 h at 80 °C; (2) organyl halides (2.0 eq) for 3–5 h at 25–153 °C. Using this condition, 18 various diorganyl tellurides 1 were selectively and efficiently synthesized in reasonable yields (37–93%). The reaction pathways for the formation of diorganyl tellurides 1 were also investigated. Consequently, we established a practical and efficient method for the selective synthesis of diorganyl tellurides 1 as a representative class of organotellurium compounds. Full article

(This article belongs to the Special Issue Featured Papers in Organometallic Chemistry—2nd Edition)

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14 pages, 609 KiB

Open AccessArticle

Pd-Catalyzed Aromatic Dual C-H Acylations and Intramolecular Cyclization: Access to Quinoline-Substituted Hydroxyl Isoindolones

by Hongke Xu, Yuchen Yang, Fei Li and Yuzhu Yang

Molecules 2024, 29(22), 5397; https://doi.org/10.3390/molecules29225397 (registering DOI) - 15 Nov 2024

Abstract

A palladium-catalyzed aromatic dual C-H acylations followed with intramolecular cyclizations have been developed by the assistance of bidentate N-(quinolin-8-yl)benzamide. This tandem process involves the formation of three new chemical bonds, providing access to novel quinoline-substituted hydroxyl isoindolones skeleton under simple reaction conditions. [...] Read more.

A palladium-catalyzed aromatic dual C-H acylations followed with intramolecular cyclizations have been developed by the assistance of bidentate N-(quinolin-8-yl)benzamide. This tandem process involves the formation of three new chemical bonds, providing access to novel quinoline-substituted hydroxyl isoindolones skeleton under simple reaction conditions. The deuterium-labeled competition reaction has revealed that C-H bond cleavage is the turnover limiting step. Full article

(This article belongs to the Special Issue Advances in Heterocyclic Synthesis)

12 pages, 715 KiB

Open AccessArticle

Covalent vs. Dative Bonding in Carbon Monoxide and Other 10-Valence-Electron Diatomics

by Khadija Rizwan and John Morrison Galbraith

Molecules 2024, 29(22), 5396; https://doi.org/10.3390/molecules29225396 (registering DOI) - 15 Nov 2024

Abstract

Valence bond theory (VB) was used to determine the extent and driving forces for covalent vs. dative bonding in 10-valence-electron diatomic molecules N₂, CO, NO⁺, CN⁻, P₂, SiS, PS⁺, and SiP⁻. [...] Read more.

Valence bond theory (VB) was used to determine the extent and driving forces for covalent vs. dative bonding in 10-valence-electron diatomic molecules N₂, CO, NO⁺, CN⁻, P₂, SiS, PS⁺, and SiP⁻. VBSCF calculations were performed at the CCSD(T)/cc-pVDZ optimized geometries. The full triply bonded system included 20 VB structures. A separation of the σ and π space allowed for a subdivision of the full 20 structure set into sets of 8 and 3 for the π and σ systems, respectively. The smaller structure sets allowed for a more focused look at each type of bond. In situ bond energies for σ bonds, individual π bonds, the π system, and triple bonds follow expected trends. Our data shows that N₂ and P₂ have three covalent bonds whereas CO and SiS contain two covalent and one dative bond, and charged species NO⁺, CN⁻, PS⁺, and SiP⁻ are a mixture of N₂ and CO type electronic arrangements, resulting in a nearly equal charge distribution. Dative bonds prefer to be in the π position due to enhanced σ covalency and π resonance. Both σ and π resonance energies depend on a balance of ionic strength, orbital compactness, σ constraints, and bond directionality. Resonance energy is a major contributor to bond strength, making up more than 50% of the π bonds in SiS and PS⁺ (charge-shift bonds), and is greater than charge transfer in dative bonds. Full article

(This article belongs to the Section Physical Chemistry)

12 pages, 2513 KiB

Open AccessArticle

Comparative Metabolomic Analysis of the Nutrient Composition of Different Varieties of Sweet Potato

by Xiaolin Wan, Xiuzhi Wang and Qiang Xiao

Molecules 2024, 29(22), 5395; https://doi.org/10.3390/molecules29225395 (registering DOI) - 15 Nov 2024

Abstract

Sweet potatoes are rich in amino acids, organic acids, and lipids, offering exceptional nutritional value. To accurately select varieties with higher nutritional value, we employed liquid chromatography–tandem mass spectrometry (LC-MS/MS) to analyze the metabolic profiles of three types of sweet potatoes (white sweet [...] Read more.

Sweet potatoes are rich in amino acids, organic acids, and lipids, offering exceptional nutritional value. To accurately select varieties with higher nutritional value, we employed liquid chromatography–tandem mass spectrometry (LC-MS/MS) to analyze the metabolic profiles of three types of sweet potatoes (white sweet potato flesh, BS; orange sweet potato flesh, CS; and purple sweet potato flesh, ZS). When comparing CS vs. BS, ZS vs. BS, and ZS vs. CS, we found differences in 527 types of amino acids and their derivatives, 556 kinds of organic acids, and 39 types of lipids. After excluding the derivatives, we found 6 amino acids essential for humans across the three sweet potatoes, with 1 amino acid, 11 organic acids, and 2 lipids being detected for the first time. CS had a higher content of essential amino acids, while ZS had a lower content. Succinic acid served as a characteristic metabolite for ZS, helping to distinguish it from the other two varieties. These findings provide a theoretical basis for assessing the nutritional value of sweet potatoes and setting breeding targets while facilitating the selection of optimal varieties for food processing, medicine, and plant breeding. Full article

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Figure 1
HCA, PCA, and Venn diagrams for the three types of sweet potatoes. (A) HCA diagram for lipids. (B) HCA diagram for organic acids. (C) HCA diagram for amino acids and their derivatives. Columns in the HCA diagram represent each variety of sweet potato, and rows represent each metabolite. Orange indicates a relatively high metabolite abundance, while blue indicates a relatively low abundance. (D) PCA score plot for the three types of sweet potatoes. (E) Venn diagram of the differential metabolites in the three comparison groups. Full article ">Figure 2
Differential metabolite analysis of the three sweet potato species. The score plots for (A) BS vs. CS, (B) BS vs. ZS, and (C) CS vs. ZS were derived using orthogonal partial least squares discriminant analysis (OPLS-DA). The volcano plots for (D) BS vs. CS, (E) BS vs. ZS, and (F) CS vs. ZS showed different levels of metabolites. Full article ">Figure 3
KEGG annotations. (A) Differential accumulation enrichment results of the three metabolites for CS vs. BS, (B) ZS vs. BS, and (C) ZS vs. CS. Horizontal coordinates represent the number of differential metabolites enriched in a pathway (orange represents the number of differential metabolites between CS vs. BS, yellow represents the number of differential metabolites between ZS vs. BS, and green represents the number of differential metabolites between ZS vs. CS); vertical coordinates represent the KEGG pathway names. The horizontal coordinates indicate the number of metabolites annotated in each pathway. Full article ">Figure 4
Peak area plots of several amino acids, organic acids, and lipids. (A–F): peak area values for several common organic acids; (G–L): peak area values for several common lipids; (M–P): peak area values of four human essential amino acids. * represents p ≤ 0.05; ** represents p ≤ 0.01; *** represents p ≤ 0.001. Blue represents BS, white represents CS, and orange represents ZS. Full article ">

12 pages, 1532 KiB

Open AccessReview

Aromaticity and Chirality: New Facets of Old Concepts

by Bagrat A. Shainyan

Molecules 2024, 29(22), 5394; https://doi.org/10.3390/molecules29225394 - 15 Nov 2024

Abstract

The review summarizes the results of previous and the latest studies on aromaticity and related concepts. The electron counting rule for 3D-aromatic systems 2(n + 1)² is shown to be a generalization of the 4n + 2 rule for planar molecules, and, [...] Read more.

The review summarizes the results of previous and the latest studies on aromaticity and related concepts. The electron counting rule for 3D-aromatic systems 2(n + 1)² is shown to be a generalization of the 4n + 2 rule for planar molecules, and, vice versa, the latter can be derived from the former. The relative stability of the push–pull and captodative aromatic systems is shown to depend on the nature of the groups separated by the C=C bond in geminal or vicinal positions. The fully symmetrical molecules of hexamethylbenzene and hexacyanobenzene were studied using structural, energetic, and NMR criteria, and the donor substituents were shown to increase the aromaticity. Taking into account the coincidence of the number of π-electrons in aromatic systems with the number of electrons on the filled electron subshells (s, p, d, and f) and considering electrons as objects in a space of states allowed to conclude that no g-elements can exist and that the extension of the Periodic Table is possible only by filling 6f, 7d, or 8s subshells. The dimensionality of space also affects the chirality of molecules, making planar or even linear molecules chiral on oriented surfaces, which can be used for the preparation of enantiomerically pure drugs, resolution of prochiral compounds, etc. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Organic Chemistry Section of Molecules)

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13 pages, 3871 KiB

Open AccessArticle

LC-MS/MS-Based Site-Specific N-Glycosylation Analysis of VEGFR-IgG Fusion Protein for Sialylation Assessment Across IEF Fractions

by Kwang Hoe Kim, Eun Sun Ji, Ju Yeon Lee, Ju Hwan Song and Yeong Hee Ahn

Molecules 2024, 29(22), 5393; https://doi.org/10.3390/molecules29225393 - 15 Nov 2024

Abstract

The glycosylation profile of therapeutic proteins significantly influences their efficacy, stability, and immunogenicity. Sialylation is crucial for the biological activity and pharmacokinetics of fusion proteins used in treating angiogenic disorders, making sialic acid levels a critical quality attribute in the development and production [...] Read more.

The glycosylation profile of therapeutic proteins significantly influences their efficacy, stability, and immunogenicity. Sialylation is crucial for the biological activity and pharmacokinetics of fusion proteins used in treating angiogenic disorders, making sialic acid levels a critical quality attribute in the development and production of biologics. In this study, we employed a mass spectrometry-based approach to assess sialylation levels through site-specific N-glycosylation analysis. To validate the method’s effectiveness, IEF fractions (acidic, main, and basic) obtained from the production media of the VEGFR-IgG fusion protein and anticipated to exhibit varying sialylation levels were analyzed. Our analytical method successfully evaluated the sialylation levels of each domain—IgG, VEGFR-1, and VEGFR-2—within the Fc-fusion protein. The results confirm that the overall sialylation level of the Fc-fusion protein correlated with the levels observed across the IEF fractions. This finding highlights the value of LC-MS/MS-based sialylation monitoring as a crucial tool for biosimilar development and quality control, particularly in optimizing target protein production. Additionally, glycopeptide-based LC-MS analysis enables site-specific sialylation evaluation, ensuring consistent profiles for robust quality assurance. Full article

(This article belongs to the Section Analytical Chemistry)

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Figure 1
Isoelectric focusing (IEF) fractions of the VEGFR-IgG fusion protein. The gel shows the separation of protein charge variants in the pH range of 3.5 to 8.3. Lane M represents the molecular weight marker with pI values indicated on the left. Lanes labeled standard sample 1 (STD 1) and standard sample 2 (STD 2) correspond to standard samples. Lanes labeled Main1, Main2, and Main3 represent the main protein samples. Basic1 and Basic2 correspond to the basic protein variants, while the acidic lane represents the acidic protein variant. The observed band patterns indicate the distribution of charge variants across the different samples, with distinct differences in the band intensities and positions reflecting the variations in protein isoelectric points (pI) among the main, basic, and acidic samples. Full article ">Figure 2
(a1) and (b1) HCD, (a2) and (b2) CID, and (a3) and (b3) EThcD spectra for the LVLNCTAR_5_4_0_0_0 (non-sialylated) and LVLNCTAR_5_4_0_2_0 (sialylated) N-glycopeptides identified in the main sample. The italic underlined N letter is the N-glycosylation site. These glycopeptides are composed of N-Acetylglucosamine (GlcNAc, blue), Mannose (Man, green), Galactose (Gal, yellow), and Sialic acid (NeuAc, purple). Full article ">Figure 3
The relative abundance of N-glycosylation across three different samples: basic, main, and acidic. The y-axis represents the relative abundance of N-glycosylation, which is scaled from 0 to 100 percent. Each bar in the figure is divided into different colored segments, representing various types of N-glycosylation: C/H (complex/hybrid type), C/H-F (complex/hybrid type with fucose), C/H-FS (complex/hybrid type with fucose and sialic acid), C/H-S (complex/hybrid type with sialic acid), and HM (high-mannose type). Full article ">Figure 4
A comparison of the different N-glycoforms in the (a) VEGFR-1, (b) VEGFR-2, and (c) IgG domains across the three samples: basic, main, and acidic. The different glycoforms are represented by different colors in the bar chart. Blue (VEGFR-1-C/H), yellow (VEGFR-1-C/H-F), green (VEGFR-1-C/H-FS), pink (VEGFR-1-C/H-S), and purple (VEGFR-1-HM). Full article ">Figure 5
The relative abundance of N-glycopeptides with and without sialic acid of the complex type across the three different samples. Full article ">

13 pages, 2179 KiB

Open AccessArticle

Smart and Efficient Synthesis of Cyclic Poly(N-isopropylacrylamide)s by Ring Expansion RAFT (RE-RAFT) Polymerization and Analysis of Their Unique Temperature-Responsive Properties

by Jin Motoyanagi, Kenichi Bessho and Masahiko Minoda

Molecules 2024, 29(22), 5392; https://doi.org/10.3390/molecules29225392 - 15 Nov 2024

Abstract

Cyclic polymers have many interesting properties compared to their linear analogs, but there are very few examples of their synthesis. This is because most cyclic polymers have been synthesized by stepwise processes, including synthesizing homo- or hetero-telechelic end-functionalized precursor polymers and consecutive intramolecularly [...] Read more.

Cyclic polymers have many interesting properties compared to their linear analogs, but there are very few examples of their synthesis. This is because most cyclic polymers have been synthesized by stepwise processes, including synthesizing homo- or hetero-telechelic end-functionalized precursor polymers and consecutive intramolecularly coupling of both ends of the polymers. This requires a complicated synthesis, and the product yields are very low because the target cyclic polymers are usually synthesized under highly dilute conditions, consequently, making it difficult to systematically analyze the properties of cyclic polymers. In the present research, we have synthesized cyclic polymers using a ring expansion polymerization method. Particularly, the ring expansion RAFT polymerization (RE-RAFT polymerization) that we have developed using a cyclic chain transfer agent is a smart method that can synthesize cyclic polymers very efficiently. In this paper, we successfully synthesized cyclic-poly(N-isopropylacrylamide), which is widely known as a thermo-responsive polymer, by RE-RAFT polymerization. Furthermore, we have compared the thermo-responsive properties of the cyclic-poly(N-isopropylacrylamide)s with those of their linear analogs. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Application of Polymer-Based Materials)

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A time-conversion curve (black circles) and pseudo-first-order kinetic plot (white circles) for the polymerization of NIPAM. Polymerization was conducted with CTTC/V-70 in acetonitrile at 60 °C ([NIPAM]0/[CTTC]0/[V-70]0 = 200/1/0.4, [NIPAM]0 = 20 wt%). Full article ">Figure 2
SEC curves of polyNIPAMs measured in THF. Polymerization was conducted with CTTC/V-70 in acetonitrile at 60 °C ([NIPAM]0/[CTTC]0/[V-70]0 = 200/1/0.4, [NIPAM]0 = 20 wt%) (Black line). SEC curves of the cleaved segment polyNIPAM from the generated polymers by RE-RAFT polymerization of NIPAM with CTTC obtained at various NIPAM conversions (Red line). Full article ">Figure 3
1H NMR spectra of (A) cyclic-polyNIPAM122 by CTTC/V-70 and (B) linear-polyNIPAM146 by DBTTC/V-70 in methanol-d4 and DMSO-d6. Full article ">Figure 4
MALDI-TOF MS of the cyclic-polyNIPAM30 (matrix: 9-nitroanthracene; cationizing agent: sodium trifluoroacetate). Full article ">Figure 5
Temperature dependences of optical transmittance at 500 nm obtained for 1.0 g/L aqueous solutions of (a) cyclic-polyNIPAM360 and (b) linear-polyNIPAM450. Full article ">Scheme 1
RAFT polymerization of NIPAM (a) with CTTC as a cyclic RAFT agent and (b) with DBTTC as an acyclic RAFT agent. Full article ">Scheme 2
Schematic of ring-expansion RAFT polymerization of NIPAM with a cyclic RAFT reagent CTTC containing “ring-expansion paths” and “ring-fusion paths”. Full article ">Scheme 3
The hydrolysis of the cyclic-polyNIPAM with hexylamine followed by the Michael addition reaction with TBA. Full article ">

30 pages, 6947 KiB

Open AccessArticle

Epigallocatechin Gallate Enzymatic Alpha Glucosylation Potentiates Its Skin-Lightening Activity—Involvement of Skin Microbiota

by Cloé Boira, Emilie Chapuis, Laura Lapierre, Daniel Auriol, Cyrille Jarrin, Patrick Robe, Jean Tiguemounine, Amandine Scandolera and Romain Reynaud

Molecules 2024, 29(22), 5391; https://doi.org/10.3390/molecules29225391 - 15 Nov 2024

Abstract

(1) Background: Ultraviolet radiation takes part in photoaging and pigmentation disorders on skin. Epigallocatechin gallate (EGCG) is a well-known brightening and photoprotective compound but it faces limitations in terms of stability and solubility. (2) Methods: A more stable and water-soluble glucoside called EGCG-G1 [...] Read more.

(1) Background: Ultraviolet radiation takes part in photoaging and pigmentation disorders on skin. Epigallocatechin gallate (EGCG) is a well-known brightening and photoprotective compound but it faces limitations in terms of stability and solubility. (2) Methods: A more stable and water-soluble glucoside called EGCG-G1 was obtained by enzymatic glucosylation of EGCG. In vitro and ex vivo experiments evaluated EGCG-G1 skin penetration, antioxidant activity, and antimelanogenic properties compared to EGCG. This gene expression study characterized the pathways impacted by EGCG-G1. Four clinical studies covering phototypes I to V, at various ages, and different skin areas, using several tools, were conducted to assess the effect of EGCG-G1 on skin hyperpigmentation and tone. The impact of glucoside on skin microbiota, especially Lactobacillus sp., was assessed through in vitro and in vivo investigations. (3) Results: EGCG-G1 better penetrated the epidermis than EGCG due to a possible interaction with GLUT1. EGCG-G1 presented similar antioxidant activity to that of EGCG and decreased melanogenesis through the inhibition of 13 genes, including MITF. The skin Lactobacillus population increased with EGCG-G1, which promoted bacterial growth in vitro as prebiotic, and induced the release of a microbial brightening metabolite. Clinical trials demonstrated EGCG-G1 to decrease hyperpigmented spots and increase skin brightness and homogeneity in a large panel of phototypes, outperforming EGCG and vitamin C. (4) Conclusions: Glucosylation of EGCG maintained its photoprotective antioxidant properties and enhanced penetration across the epidermis. EGCG-G1 demonstrated brightening properties on all skin types by down-regulation of melanogenesis pathways and indirectly by skin microbiota stimulation. Full article

(This article belongs to the Section Food Chemistry)

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18 pages, 6312 KiB

Open AccessArticle

Identification and Analysis of Anticancer Therapeutic Targets from the Polysaccharide Krestin (PSK) and Polysaccharopeptide (PSP) Using Inverse Docking

by Carlos Iván López-Gil, Alejandro Téllez-Jurado, Marco Antonio Velasco-Velázquez and Miguel Angel Anducho-Reyes

Molecules 2024, 29(22), 5390; https://doi.org/10.3390/molecules29225390 - 15 Nov 2024

Abstract

The natural compounds PSK and PSP have antitumor and immunostimulant properties. These pharmacological benefits have been documented in vitro and in vivo, although there is no information in silico which describes the action mechanisms at the molecular level. In this study, the inverse [...] Read more.

The natural compounds PSK and PSP have antitumor and immunostimulant properties. These pharmacological benefits have been documented in vitro and in vivo, although there is no information in silico which describes the action mechanisms at the molecular level. In this study, the inverse docking method was used to identify the interactions of PSK and PSP with two local databases: BPAT with 66 antitumor proteins, and BPSIC with 138 surfaces and intracellular proteins. This led to the identification interactions and similarities of PSK and the AB680 inhibitor in the active site of CD73. It was also found that PSK binds to CD59, interacting with the amino acids APS22 and PHE23, which coincide with the rlLYd4 internalization inhibitor. With the isoform of the K-RAS protein, PSK bonded to the TYR32 amino acid at switch 1, while with BAK it bonded to the region of the α1 helix, while PSP bonded to the activation site and the C-terminal and N-terminal ends of that helix. In Bcl-2, PSK interacted at the binding site of the Venetoclax inhibitor, showing similarities with the amino acids ASP111, VAL133, LEU137, MET115, PHE112, and TYR108, while PSP had similarities with THR132, VAL133, LEU137, GLN118, MET115, APS111, PHE112, and PHE104. Full article

(This article belongs to the Section Computational and Theoretical Chemistry)

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11 pages, 2387 KiB

Open AccessArticle

Excitation-Power-Dependent Color Tuning in a Single Sn-Doped CdS Nanowire

by Ye Tian, Shangfei Yao and Bingsuo Zou

Molecules 2024, 29(22), 5389; https://doi.org/10.3390/molecules29225389 - 15 Nov 2024

Viewed by 46

Abstract

Multicolor emission and dynamic color tuning with large spectral range are challenging to realize but critically important in many areas of technology and daily life, such as general lighting, display, multicolor detection and multi-band communication. Herein, we report an excitation-power-dependent color-tuning emission from [...] Read more.

Multicolor emission and dynamic color tuning with large spectral range are challenging to realize but critically important in many areas of technology and daily life, such as general lighting, display, multicolor detection and multi-band communication. Herein, we report an excitation-power-dependent color-tuning emission from an individual Sn-doped CdS nanowire with a large spectral range and continuous color tuning. Its photoluminescence (PL) spectrum shows a broad trap-state emission band out of Sn dopants, which is superposed by whispering-gallery (WG) microcavity due to the nanostructure size and its structure, besides the CdS band-edge emission. By simply changing the excitation power from 0.25 to 1.36 mW, we demonstrate that the typical Sn-doped CdS nanowire with the weight ratio of 10:1 of CdS and SnO₂, the emission color can change from red to orange to yellow to green. In view of the stable properties and large spectral range, the Sn-doped CdS nanowires are very promising potential candidates in nanoscale optoelectronic devices. Full article

(This article belongs to the Section Physical Chemistry)

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Morphology of CdS nanowire (a). SEM image of Sn-doped CdS nanowire dispersed on Si substrate. (b) EDS profiles of a typical Sn-doped CdS nanowire in (a). (c) The high magnification image of Sn-doped CdS nanowire. (d–f) The SEM elements mapping Cd, S and Sn. (g–j) PL spectra of samples with different ratio of CdS and SnO2. Full article ">Figure 2
The structure of the Sn-doped CdS nanowire. (a) XRD spectrum of Sn-doped CdS nanowire. (b) PL spectrum of the Sn-doped CdS nanowire at the excitation power of 0.251 mW. (c) Schematic illustration of the luminescence of Sn-doped CdS nanostructure at room temperature. Full article ">Figure 3
Optical lighting behavior of Sn-doped CdS nanowires with different CdS and SnO2 weight ratios. (a) Real-color PL image with focused excitation (405 nm) of each Sn-doped CdS nanowires, left is 0.576 mW, right is 1.36 mW. (b,c) PL spectra recorded at 0.251 mW and 1.36 mW, as followed by samples A, B, C and D, respectively. Full article ">Figure 4
Real-color image of excitation-power-dependent color tuning and corresponding PL spectra of the Sn-doped CdS nanowire (a–e). The real-color image at 0.251 mW, 0.576 mW, 0.922 mW, 1.13 mW and 1.36 mW. (f–j) The corresponding PL spectra. Full article ">Figure 5
The mechanism of lighting emission. (a) Excitation-power-dependent wavelength shift of four-color emission peak. (b) Excitation-power-dependent intensity shift of four-color emission peak. (c) The CIE chromaticity diagram of Sn-doped CdS nanowire. (d) Excitation-power-dependent energy level of the transition radiation process of Sn-doped CdS nanowire. Full article ">

31 pages, 839 KiB

Open AccessReview

Using Ionic Liquids to Improve CO₂ Capture

by Francisco Jose Alguacil and Jose Ignacio Robla

Molecules 2024, 29(22), 5388; https://doi.org/10.3390/molecules29225388 - 15 Nov 2024

Viewed by 102

Abstract

Most of our energy consumption proceeds from the use of fossil fuels and the production of natural gas. However, the presence of impurities in this gas, like CO₂, makes treatment necessary to avoid further concerns, such as greenhouse gas emissions, the [...] Read more.

Most of our energy consumption proceeds from the use of fossil fuels and the production of natural gas. However, the presence of impurities in this gas, like CO₂, makes treatment necessary to avoid further concerns, such as greenhouse gas emissions, the corrosion of industrial equipment, etc.; thus, the development of CO₂ capture and storage procedures is of the utmost importance in order to decrease CO₂ production and mitigate its contribution to global warming. Among the CO₂ capture processes available, three separation technologies are being used to achieve this goal: absorption, adsorption and membranes. To overcome some limitations of these methodologies, the joint use of these technologies with ionic liquids is gaining interest. The present work reviewed the most recent developments (for 2024) in CO₂ capture using ionic liquids coupled to absorption-, adsorption- or membrane-based processes. Full article

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24 pages, 1264 KiB

Open AccessReview

Spirulina—An Invaluable Source of Macro- and Micronutrients with Broad Biological Activity and Application Potential

by Izabela Podgórska-Kryszczuk

Molecules 2024, 29(22), 5387; https://doi.org/10.3390/molecules29225387 - 15 Nov 2024

Viewed by 132

Abstract

With population growth expected in the near future and the planet’s limited resources, alternative food sources are already being looked for. In this context, spirulina is called the food of the future due to its rich nutritional composition. This blue–green alga is primarily [...] Read more.

With population growth expected in the near future and the planet’s limited resources, alternative food sources are already being looked for. In this context, spirulina is called the food of the future due to its rich nutritional composition. This blue–green alga is primarily a valuable source of protein (55–70%) containing all essential amino acids. In its composition, it also contains unsaturated fatty acids, minerals, vitamins, and pigments, including the valuable protein–pigment complex—phycocyanin. Due to its high content of complete protein and minerals such as iron and calcium, it is an excellent addition to diets, especially those of vegans and vegetarians. Despite several limitations to the use of spirulina, including its distinctive marine flavour, low consumer awareness, or relatively high price, scientists are attempting to enrich many food products with the microalga. This is supported not only by the improved nutritional composition of the fortified product but also by spirulina’s impact on sustainable food production. Therefore, this review aims to create consumer attention by presenting spirulina as a valuable and sustainable food source with health-promoting potential and great future significance. Full article

(This article belongs to the Special Issue Isolation, Identification, and Applications of Bioactive Compounds from Marine Plants)

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11 pages, 3913 KiB

Open AccessArticle

Molecular Docking of Endolysins for Studying Peptidoglycan Binding Mechanism

by Arina G. Arakelian, Gennady N. Chuev and Timur V. Mamedov

Molecules 2024, 29(22), 5386; https://doi.org/10.3390/molecules29225386 - 15 Nov 2024

Viewed by 86

Abstract

Endolysins of bacteriophages, which degrade the bacterial cell wall peptidoglycan, are applicable in many industries to deal with biofilms and bacterial infections. While multi-domain endolysins have both enzymatically active and cell wall-binding domains, single-domain endolysins consist only of an enzymatically active domain, and [...] Read more.

Endolysins of bacteriophages, which degrade the bacterial cell wall peptidoglycan, are applicable in many industries to deal with biofilms and bacterial infections. While multi-domain endolysins have both enzymatically active and cell wall-binding domains, single-domain endolysins consist only of an enzymatically active domain, and their mechanism of peptidoglycan binding remains unexplored, for this is a challenging task experimentally. This research aimed to explore the binding mechanism of endolysins using computational approaches, namely molecular docking and bioinformatical tools, and analyze the performance of these approaches. The docking engine Autodock Vina 1.1.2 and the 3D-RISM module of AmberTools 24 were studied in the current work and used for receptor–ligand affinity and binding energy calculations, respectively. Two possible mechanisms of single-domain endolysin–ligand binding were predicted by Autodock Vina and verified by the 3D-RISM. As a result, the previously obtained experimental results on peptidoglycan binding of the isolated gamma phage endolysin PlyG enzymatically active domain were supported by molecular docking. Both methods predicted that single-domain endolysins are able to bind peptidoglycan, with Autodock Vina being able to give accurate numerical estimates of protein–ligand affinities and 3D-RISM providing comparative values. Full article

(This article belongs to the Special Issue Molecular Modeling: Advancements and Applications, 3rd Edition)

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N-terminus binding of endolysins Endo T5-Zn2+ (left) and Endo T5-Zn2+/Ca2+ (right) to the NAG-NAM ligand, with Zn2+ ion represented by green spheres and Ca2+ represented by a blue sphere. Full article ">Figure 2
“Cavity” binding of endolysins Endo T5-Zn2+ (left) and Endo T5-Zn2+/Ca2+ (right) to NAM and CC-DPS CT1103206303 ligands, respectively, with Zn2+ ion represented by green spheres and Ca2+ represented by a blue sphere. Full article ">Figure 3
PlyG EAD bound to muramyl pentapeptide, with Zn2+ ion represented by a green sphere. Full article ">Figure 4
EndoT5 Zn2+-Ca2+ binding peptidoglycan monomer (left) and CC-DPS CT1103206303 (right) as examples of N-terminal and “cavity” binding processes, respectively. The yellow dotted line represents distances between atoms that are less or equal to 2.5 Å, corresponding to hydrogen bonds; atoms of F3 (left) and amino acid residues participating in ligand binding (right) are signed. Red circles denote the bond of the peptidoglycan that is cleaved by EndoT5. Full article ">Figure 5
Single-domain endolysins Endo T5-Zn2+ (left) and Endo T5-Zn2+/Ca2+ (right) with Zn2+ ion represented by green spheres and Ca2+ represented by an orange sphere. Full article ">Figure 6
Multi-domain endolysin PlyG divided into EAD (left) and CBD (right) with the Zn2+ ion represented by a blue sphere. Full article ">Figure 7
Ligand structures: NAG (A), NAM (B), NAG-NAM (C), NAM-L-Ala (D), NAM-L-Ala-ϒ-D-Glu (E), CC-DPS CT1103206303 (F), muramyl pentapeptide (G), peptidoglycan monomer (H), and pentaglycine (I). Full article ">

14 pages, 7281 KiB

Open AccessArticle

Ti³⁺ Self-Doping of TiO₂ Boosts Its Photocatalytic Performance: A Synergistic Mechanism

by Mingqing Zhang, Manyu Liu, Keyi Han, Yingbin Liang, Xinyu Zhao, Lin Han, Jinnong Wang, Shifeng Wang and Yong Li

Molecules 2024, 29(22), 5385; https://doi.org/10.3390/molecules29225385 - 15 Nov 2024

Viewed by 70

Abstract

Pollution remains one of the most significant global challenges. Photocatalysis consists of a new organic pollutant removal technology, with TiO₂ widely studied as a photocatalyst in the photocatalytic removal of water pollution. However, intrinsic TiO₂ has the disadvantages of weak visible [...] Read more.

Pollution remains one of the most significant global challenges. Photocatalysis consists of a new organic pollutant removal technology, with TiO₂ widely studied as a photocatalyst in the photocatalytic removal of water pollution. However, intrinsic TiO₂ has the disadvantages of weak visible light absorption, low electron separation, and transmission efficiency, as well as few active sites. In this study, anatase-phase Ti³⁺ self-doped TiO₂ (B-TiO₂) with a core-shell structure was successfully prepared by forming an amorphous layer rich in oxygen vacancies (OVs) and Ti³⁺ defects on the TiO₂ surface under a nitrogen atmosphere using NaBH₄ as a chemical-reducing agent. The visible light absorption performance of the catalyst was notably improved when exposed to light irradiation. The bending of surface energy bands facilitated the separation of photogenerated electron-hole pairs, and the core-shell structure allowed the electron-hole pairs to be transported to the surface of the catalyst and participate in the reaction faster. We observed that 92.86% of Rhodamine B (RhB) was degraded in only 5 min, an increase of 2.73 times that of the degradation rate observed in commercial P25. With extraordinary stability, the photocatalytic efficiency of the catalyst remained at 96.2% after five degradation cycles. Full article

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16 pages, 2056 KiB

Open AccessArticle

Synthesis and Antimicrobial Activity of 3-Alkylidene-2-Indolone Derivatives

by He Huang, Yating Zhang, Qiu Du, Changji Zheng, Chenghua Jin and Siqi Li

Molecules 2024, 29(22), 5384; https://doi.org/10.3390/molecules29225384 - 15 Nov 2024

Viewed by 118

Abstract

The escalating threat of antibiotic-resistant bacteria and fungi underscores an urgent need for new antimicrobial agents. This study aimed to synthesize and evaluate the antimicrobial activities of two series of 3-alkylidene-2-indolone derivatives. We synthesized 32 target compounds, among which 25 exhibited moderate to [...] Read more.

The escalating threat of antibiotic-resistant bacteria and fungi underscores an urgent need for new antimicrobial agents. This study aimed to synthesize and evaluate the antimicrobial activities of two series of 3-alkylidene-2-indolone derivatives. We synthesized 32 target compounds, among which 25 exhibited moderate to high antibacterial or antifungal activities. Notably, compounds 10f, 10g, and 10h demonstrated the highest antibacterial activity with a minimum inhibitory concentration (MIC) of 0.5 μg/mL, matching the activity of the positive control gatifloxacin against three Gram-positive bacterial strains: Staphylococcus aureus ATCC 6538, 4220, and Methicillin-resistant Staphylococcus aureus ATCC 43300. Moreover, the three most active compounds 10f, 10g, and 10h were evaluated for their in vitro cytotoxicity in the HepG2 cancer cell line and L-02; only compound 10h was found to exert some level of cytotoxicity. These findings suggest that the synthesized 3-alkylidene-2-indolone derivatives hold potential for further development as antibacterial agents. Full article

(This article belongs to the Special Issue Fused-Nitrogen-Containing Heterocycles (Second Edition))

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21 pages, 4041 KiB

Open AccessArticle

Unexpected XPS Binding Energy Observations Further Highlighted by DFT Calculations of Ruthenocene-Containing [Ir^III(ppy)₂(RCOCHCORc)] Complexes: Cytotoxicity and Crystal Structure of [Ir(ppy)₂(FcCOCHCORc)]

by Blenerhassitt E. Buitendach, Elizabeth Erasmus, Eleanor Fourie, Frederick P. Malan, Jeanet Conradie, J. W. (Hans) Niemantsverdriet and Jannie C. Swarts

Molecules 2024, 29(22), 5383; https://doi.org/10.3390/molecules29225383 - 15 Nov 2024

Viewed by 140

Abstract

The series of iridium(III) complexes, [Ir(ppy)₂(RCOCHCOR′)], with R = CH₃ and R′ = CH₃ (1), Rc (2), and Fc (3), as well as R = Rc and R′ = Rc (4) [...] Read more.

The series of iridium(III) complexes, [Ir(ppy)₂(RCOCHCOR′)], with R = CH₃ and R′ = CH₃ (1), Rc (2), and Fc (3), as well as R = Rc and R′ = Rc (4) or Fc (5), and R = R′ = Fc (6), ppy = 2-phenylpyridinyl, Fc = Fe^II(η⁵–C₅H₄)(η⁵–C₅H₅), and Rc = Ru^II(η⁵–C₅H₄)(η⁵–C₅H₅), has been investigated by single-crystal X-ray crystallography and X-ray photoelectron spectroscopy (XPS) supplemented by DFT calculations. Here, in the range of 3.74 ≤ Σχ_R ≤ 4.68, for Ir 4f, Ru 3d and 3p and N 1s orbitals, binding energies unexpectedly decreased with increasing Σχ_R (Σχ_R = the sum of Gordy group electronegativities of the R groups on β-diketonato ligands = a measure of electron density on atoms), while in Fe 2p orbitals, XPS binding energy, as expected, increased with increasing Σχ_R. Which trend direction prevails is a function of main quantum level, n = 1, 2, 3…, sub-quantum level (s, p, d, and f), initial state energies, and final state relaxation energies, and it may differ from compound series to compound series. Relations between DFT-calculated orbital energies and Σχ_R followed opposite trend directions than binding energy/Σχ_R trends. X-ray-induced decomposition of compounds was observed. The results confirmed good communication between molecular fragments. Lower binding energies of both the Ir 4f_7/2 and N 1s photoelectron lines are associated with shorter Ir-N bond lengths. Cytotoxic tests showed that 1 (IC₅₀ = 25.1 μM) and 3 (IC₅₀ = 37.8 μM) are less cytotoxic against HeLa cells than cisplatin (IC₅₀ = 1.1 μM), but more cytotoxic than the free β-diketone FcCOCH₂COCH₃ (IC₅₀ = 66.6 μM). Full article

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17 pages, 2168 KiB

Open AccessArticle

Unveiling the Anticancer Potential of a New Ciprofloxacin-Chalcone Hybrid as an Inhibitor of Topoisomerases I & II and Apoptotic Inducer

by Doaa Mohamed Elroby Ali, Hossameldin A. Aziz, Stefan Bräse, Areej Al Bahir, Abdullah Alkhammash, Gamal El-Din A. Abuo-Rahma, Ali M. Elshamsy, Hamada Hashem and Walid M. Abdelmagid

Molecules 2024, 29(22), 5382; https://doi.org/10.3390/molecules29225382 - 15 Nov 2024

Viewed by 164

Abstract

The current study has yielded promising results in the evaluation of a new ciprofloxacin-chalcone hybrid (CP derivative) for its anticancer activity as potential Topoisomerases (Topo) I and II inhibitors. The in vitro results showed that the CP derivative significantly suppressed the growth of [...] Read more.

The current study has yielded promising results in the evaluation of a new ciprofloxacin-chalcone hybrid (CP derivative) for its anticancer activity as potential Topoisomerases (Topo) I and II inhibitors. The in vitro results showed that the CP derivative significantly suppressed the growth of HCT-116 and LOX IMVI cells, with IC₅₀ values of 5.0 μM and 1.3 μM, respectively, outperforming Staurosporine, which had IC₅₀ values of 8.4 μM and 1.6 μM, respectively. Flow cytometry analysis revealed that the new CP derivative triggered apoptosis and cell cycle arrest at the G2/M phase, associated with the up-regulation of pro-apoptotic genes (Bax and Caspase 9) and downregulation of the anti-apoptotic gene (Bcl-2). Further investigations showed that the CP derivative inhibited Topo I and II enzymes, as expected molecular targets; docking studies further supported its dual inhibitory action on Topo I and II. These findings suggest that the ciprofloxacin-chalcone hybrid could be a promising lead compound for developing new anticancer therapy. Full article

(This article belongs to the Topic Enzymes and Enzyme Inhibitors in Drug Research)

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9 pages, 2477 KiB

Open AccessArticle

ZnCl₂-Based Deep Eutectic Solvent as Solvent-Catalyst in the Michael Addition Reaction of Pyrrole to Maleimide

by Abelardo Gutiérrez-Hernández, Fátima M. Soto-Suárez, Arlette Richaud, Francisco Méndez and Claudia Araceli Contreras-Celedón

Molecules 2024, 29(22), 5381; https://doi.org/10.3390/molecules29225381 - 15 Nov 2024

Viewed by 96

Abstract

The use of deep eutectic solvents (DESs) as catalysts presents indisputable advantages, for example, their simplicity of preparation, high biodegradability, and recyclability, as well as zero toxicity and their effectiveness as environmentally friendly reaction media. However, aspects related to their reactivity and catalytic [...] Read more.

The use of deep eutectic solvents (DESs) as catalysts presents indisputable advantages, for example, their simplicity of preparation, high biodegradability, and recyclability, as well as zero toxicity and their effectiveness as environmentally friendly reaction media. However, aspects related to their reactivity and catalytic activity are still unclear. In this work, we explore the versatility of ChCl/ZnCl₂ DES in the formation of C-C bonds through the Michael-type addition of pyrrole to maleimide, where ChCl/ZnCl₂ DES leads to catalysis and chelation of the substrates, thus describing a recommended method for the construction of C-C bonds with high atomic economy. We describe experimental and theoretical aspects that explain the ability of ChCl/ZnCl₂ DES in the presence of water to act as a catalyst in the formation of C-C bonds between pyrrole and maleimide. The potential energy surface showed that the ChCl and the zinc-zincate species 2ZnCl₂·3H₂O, formed by the interaction between zinc chloride and water, decrease the relative free Gibbs energy values for all the species involved in the reaction mechanism (TSs, intermediates, product), favoring the kinetics and thermodynamics of the Michael addition. Full article

(This article belongs to the Special Issue Advances in Deep Eutectic Solvents)

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Full article ">Figure 1
Reaction mechanism for the addition of pyrrole 1 to maleimide 2a in the presence of ChCl/ZnCl2 DES. Full article ">Figure 2
Schematic view of intermediate 1 for the reaction between pyrrole, maleimide, ChCl, and the zinc zincate species. Full article ">Figure 3
Gibbs energy profiles for the addition of pyrrole 1 to maleimide 2a in the absence and presence of ZnCl2, ChCl/ZnCl2 DES, and zinc-zincate species 2ZnCl2·3H2O. (a), (b), (c), and (d) are the set of reaction mechanisms involved in the Michael addition in this reaction. Full article ">Figure 4
Gibbs energy profiles for the addition of pyrrole 1 to maleimide 2b in the absence and presence of ZnCl2, ChCl/ZnCl2 DES, and zinc−zincate species 2ZnCl2·3H2O. (a), (b), (c), and (d) are the set of reaction mechanisms involved in the Michael addition in this reaction. Full article ">Scheme 1
Set of reactions showing the mechanisms involved in the Michael addition between pyrrole 1 and maleimides 2a and 2b with and without DES ChCl/ZnCl2. TS1= transition state 1, Int1 = intermediary 1, TS2 = transition state 2, Int2 = intermediary 2, TS3 = transition state 3, P = product. Full article ">

17 pages, 3562 KiB

Open AccessArticle

The Impact of Support and Reduction Temperature on the Catalytic Activity of Bimetallic Nickel-Zirconium Catalysts in the Hydrocracking Reaction of Algal Oil from Spirulina Platensis

by Lukasz Szkudlarek, Karolina A. Chalupka-Spiewak, Aleksandra Zimon, Michal Binczarski, Waldemar Maniukiewicz, Pawel Mierczynski and Malgorzata Iwona Szynkowska-Jozwik

Molecules 2024, 29(22), 5380; https://doi.org/10.3390/molecules29225380 - 15 Nov 2024

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Abstract

The aim of this work was to investigate the hydrocracking of algae oil derived from Spirulina Platensis species catalyzed with bi-component nickel-zirconia catalysts supported onto different carriers (BEA, ZSM-5 and Al₂O₃) in an autoclave at 320 °C for 2 [...] Read more.

The aim of this work was to investigate the hydrocracking of algae oil derived from Spirulina Platensis species catalyzed with bi-component nickel-zirconia catalysts supported onto different carriers (BEA, ZSM-5 and Al₂O₃) in an autoclave at 320 °C for 2 h with a hydrogen pressure of 75 bar. All catalysts were prepared using the wet co-impregnation method and were characterized by H₂-TPR, XRD, NH₃-TPD, BET and SEM-EDS. Before reactions, catalysts were calcined at 600 °C for 4 h in a muffle furnace, then reduced with 5%H₂-95%Ar reducing mixture at 500 °C, 600 °C or 700 °C for 2 h. The obtained products were analyzed and identified by HPLC and GC-MS techniques. In addition to the investigation of the support effect, the influence of the reduction temperature of catalytic systems on the catalytic activity and selectivity of the products was also examined. The activity results show that Ni-Zr systems supported on zeolites exhibited high conversion of algal oil. A gradual decrease in conversion was observed when increasing the reduction temperature of the catalyst (from 500 °C to 600 °C and 700 °C) for BEA zeolite catalysts. The reaction products contain hydrocarbons from C₇ to C₃₃ (for zeolite-supported catalysts) and C₃₆ (for systems on Al₂O₃). The identified hydrocarbons mainly belong to the gasoil fraction (C₁₄–C₂₂). In the research, the best catalyst for the algal oil hydrocracking reaction was found to be the 5%Ni-5%Zr/BEA system reduced at 600 °C, which exhibited the second highest algal oil conversion (94.0%). The differences in catalytic activity that occur are due to the differences in the specific surface area among the supports and to differences in the acidity of the catalyst surface depending on the reduction temperature. Full article

(This article belongs to the Special Issue Zeolites and Mesoporous Materials: Properties and Applications, 2nd Edition)

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SEM images of 5%Ni-5%ZrBEA catalyst after reduction at 600 °C. Full article ">Figure 2
SEM images of 5%Ni-5%ZrZSM-5 catalyst after reduction at 600 °C. Full article ">Figure 3
SEM images of 5%Ni-5%Zr/Al2O3 catalyst after reduction at 600 °C. Full article ">Figure 4
TPR-H2 profiles for bimetallic nickel-zirconium catalysts supported on BEA zeolite, ZSM-5 zeolite and Al2O3 after their calcination at 600 °C for 4 h. Full article ">Figure 5
XRD patterns obtained for 5%Ni-5%ZrBEA zeolite during “in situ” measurement in a reduced mixture of 5%H2-95%Ar flow in the temperature range 500–900 °C. Full article ">Figure 6
XRD patterns obtained for 5%Ni-5%ZrZSM-5 zeolite during “in situ” measurement in a reduced mixture of 5%H2-95%Ar flow in the temperature range 500–900 °C. Full article ">Figure 7
XRD patterns obtained for 5%Ni-5%Zr/Al2O3 during “in situ” measurement in a reduced mixture of 5%H2-95%Ar flow in the temperature range 500–900 °C. Full article ">

27 pages, 7765 KiB

Open AccessArticle

Carbon Nanotubes in Cement—A New Approach for Building Composites and Its Influence on Environmental Effect of Material

by Teobald Kupka, Natalina Makieieva, Paweł Świsłowski, Małgorzata Rajfur, Artur Małolepszy, Leszek Stobiński, Stefania Grzeszczyk, Krystian Jurowski, Adam Sudoł, Roman Wrzalik, Oimahmad Rahmonov and Krzysztof Ejsmont

Molecules 2024, 29(22), 5379; https://doi.org/10.3390/molecules29225379 - 14 Nov 2024

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Abstract

An addition of carbon nanostructures to cement paste is problematic due to the difficulties in obtaining homogenous mixtures. The paper reports on a more effective way of mixing carboxylated multi-walled carbon nanotubes (MWCNT-COOH) in cement pastes. The additional biological impact of the studied [...] Read more.

An addition of carbon nanostructures to cement paste is problematic due to the difficulties in obtaining homogenous mixtures. The paper reports on a more effective way of mixing carboxylated multi-walled carbon nanotubes (MWCNT-COOH) in cement pastes. The additional biological impact of the studied nanomodified cement was analyzed in the case of two moss species’ vitality. The applied approach of obtaining a homogeneous mixture is based on intense mechanochemical mixing of MWCNT-COOH together with polycarboxylate superplasticizer (SP). As a result, a more homogenous suspension of MWCNT-COOH within a liquid superplasticizer, suitable for addition to hydrophilic cement paste, was obtained. FT-IR/Raman spectroscopy was used for materials’ characterization. To explain the mixing process at the molecular level, systematic theoretical studies using density functional theory (DFT) were performed. The structures, interaction energies and IR/Raman vibrational spectra of model carboxylic acids, mixed with functionalized SWCNTs as simplified models of real MWCNTs, were obtained. Due to the controversial opinions on the environmental hazards of carbon nanostructures, additional in vivo studies were performed. In this case, effects of cement modified by the addition of small amounts of MWCNT-COOH with SP in comparison to the composite without carbon nanostructures and control subsoil on the vitality of mosses Polytrichum formosum and Pseudoscleropodium purum were studied. Full article

(This article belongs to the Special Issue Feature Papers in Applied Chemistry: 3rd Edition)

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15 pages, 8360 KiB

Open AccessArticle

Preparation of Double-Networked Slow-Expanding Nanomicrospheres and Evaluation of Drive Modulation Performance

by Qiaolin Zuo, Zhenzhong Fan, Qingwang Liu, Yuanfeng Fu, Luoqi Cui and Junfeng Yang

Molecules 2024, 29(22), 5378; https://doi.org/10.3390/molecules29225378 - 14 Nov 2024

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Abstract

Aiming at the problem of excessive swelling of conventional microspheres for oilfield use, a novel amphiphilic polymerizable crosslinker (AE) was synthesized by quaternary ammonium modification of an unstable crosslinker (AE) using acrylamide, 2-acrylamido-2-methylpropanesulfonic acid as the monomers, N,N′-methylene bisacrylamide as the stabilizing crosslinker, [...] Read more.

Aiming at the problem of excessive swelling of conventional microspheres for oilfield use, a novel amphiphilic polymerizable crosslinker (AE) was synthesized by quaternary ammonium modification of an unstable crosslinker (AE) using acrylamide, 2-acrylamido-2-methylpropanesulfonic acid as the monomers, N,N′-methylene bisacrylamide as the stabilizing crosslinker, ammonium peroxysulfate and sodium bisulfite as the initiator, and water as the solvent by using a reversed microemulsion method. Double-networked nanomicrospheres were prepared. The preparation conditions of the microspheres were optimized by the surface response method, focusing on the effects of the initiator addition and reaction temperature, and total crosslinker addition on the formation of nanomicrospheres. The samples were characterized by FTIR, TGA, laser particle sizer, and SEM to evaluate the retarded expansion performance and the modulation drive performance. The results showed that the optimal conditions for the preparation of microspheres were m(oil phase):m(water phase) = 3:2, stirring speed of 550 r/min, total crosslinking agent dosage of 0.6% (based on the total mass of monomers, hereinafter the same), initiator dosage of 0.30%, reaction temperature of 45 °C, and reaction time of 4 h. Compared with the conventional polymer microsphere PAM, PAE was slow-expanded for 45 d at 60 °C, and the expansion multiplier was about 16 times, with slow-expansion characteristics; the blocking rate of PAE reached 98.3%, the oil repulsion rate was 73.11%, and the increase in the recovery rate could be up to 11.23%. In this paper, a new type of nanomicrosphere material is investigated to realize the efficient implementation of oil field conditioning and driving. Full article

(This article belongs to the Special Issue Heterophase Polymerization and Functional Polymer Microspheres/Microcapsules)

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Effect of various factors on PAE yield and particle size Optimisation of synthesis conditions: (a,d) initiator dosage; (b,e) monomer concentration; (c,f) starting temperature. Full article ">Figure 2
SEM of double-mesh microspheres with different amounts of crosslinking agent. Full article ">Figure 3
(a) Thermogravimetric (TGA) curve of microspheres, (b) infrared curve (FTIR), (c) hydrogen nuclear magnetic resonance (HNMR) spectrum of microspheres, (d) microsphere particle size. Full article ">Figure 4
Slow-expansion performance of microspheres (a) for comparison with single-mesh microspheres; (b) for the slow-expansion time of microspheres with different crosslinker additives; (c) initial nanoscale microsphere size; (d) slow expansion at 80 °C for 48 h. Full article ">Figure 5
Mechanism of slow expansion of bi-crosslinked nanomicrospheres. Full article ">Figure 6
(a) For different concentrations; (b) for different mineralizations; (c) for the interfacial tension of the microspheres at different temperatures; (d) for the injection pressure and the resistance coefficients of the microspheres; (e) for PAM vs. PAE microsphere pressure; (f) for the microsphere drive modulation performance. Full article ">Figure 7
(a) Modification of AE crosslinking agent; (b) flow chart for the preparation of double-mesh nanospheres by reverse microemulsion method; (c) synthesis of double-mesh nanospheres by reverse microemulsion method; (d) retarded expansion of double-mesh microspheres. Full article ">

12 pages, 2457 KiB

Open AccessArticle

Vibrational Spectroscopic Identification of the [AlCl₂]⁺ Cation in Ether-Containing Liquid Electrolytes

by Gabriela P. Gomide, Wagner A. Alves and Andrzej Eilmes

Molecules 2024, 29(22), 5377; https://doi.org/10.3390/molecules29225377 - 14 Nov 2024

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Abstract

A Raman and IR study of AlCl₃-based ethereal solutions is here presented and aims at identifying the [AlCl₂]⁺ cation, which has been so far unambiguously characterized by ²⁷Al NMR spectrometry. To do that, experimental–theoretical vibrational spectroscopy was [...] Read more.

A Raman and IR study of AlCl₃-based ethereal solutions is here presented and aims at identifying the [AlCl₂]⁺ cation, which has been so far unambiguously characterized by ²⁷Al NMR spectrometry. To do that, experimental–theoretical vibrational spectroscopy was so employed, and the data are interpreted successfully. As a known amount of water is added to the tetrahydrofuran (THF)-containing electrolyte, a Raman band at 271 cm⁻¹ has its intensity increased along with the most intense band of [AlCl₄]⁻, and such behavior is also seen for a band at 405 cm⁻¹ in the IR spectra. New bands at around 420 and 400 cm⁻¹ are observed in both Raman and IR spectra for the tetraglyme (G4)-based systems. The [AlCl₂(THF)₄]⁺ complex, in the cis and trans forms, is present in the cyclic ether, while the cis-[AlCl₂(G4)]⁺ isomer is identified in the acyclic one. Full article

(This article belongs to the Section Electrochemistry)

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Raman spectra of a 0.5 mol kg−1 AlCl3 solution at the region of the νAlO and νAlCl vibrations: (a) AlCl3-THF system; (b) AlCl3-THF:H2O system with water/salt molar ratio of 0.4. Full article ">Figure 2
Far-IR spectra of a 0.5 mol kg−1 AlCl3 solution at the region of the νAlO and νAlCl modes: (a) AlCl3-THF system; (b) AlCl3-THF:H2O system with water/salt molar ratio equal to 0.4. Full article ">Figure 3
Raman spectra of AlCl3/G4 solutions at the region of the νAlO and νAlCl vibrations: (a) 1 mol kg−1; (b) 2 mol kg−1. Full article ">Figure 4
Far-IR spectra of AlCl3/G4 solutions at the region of the νAlO and νAlCl vibrations: (a) 1 mol kg−1; (b) 2 mol kg−1. Full article ">Figure 5
AIMD-simulated Raman (a) and IR (b) spectra of AlCln complexes with explicit THF solvent molecules. Full article ">Figure 6
AIMD-simulated Raman (a) and IR (b) spectra of AlCln complexes with explicit G4 solvent molecule. Full article ">Figure 7
Calculated harmonic (a) and anharmonic (b) Raman spectrum of the [AlCl4]− anion. Full article ">

27 pages, 10548 KiB

Open AccessArticle

Bioactive Three-Dimensional Chitosan-Based Scaffolds Modified with Poly(dopamine)/CBD@Pt/Au/PVP Nanoparticles as Potential NGCs Applicable in Nervous Tissue Regeneration—Preparation and Characterization

by Aleksandra Sierakowska-Byczek, Aleksandra Gałuszka, Łukasz Janus and Julia Radwan-Pragłowska

Molecules 2024, 29(22), 5376; https://doi.org/10.3390/molecules29225376 - 14 Nov 2024

Viewed by 207

Abstract

Tissue engineering of nervous tissue is a promising direction in the treatment of neurological diseases such as spinal cord injuries or neuropathies. Thanks to technological progress and scientific achievements; the use of cells; artificial scaffolds; and growth factors are becoming increasingly common. Despite [...] Read more.

Tissue engineering of nervous tissue is a promising direction in the treatment of neurological diseases such as spinal cord injuries or neuropathies. Thanks to technological progress and scientific achievements; the use of cells; artificial scaffolds; and growth factors are becoming increasingly common. Despite challenges such as the complex structure of this tissue, regenerative medicine appears as a promising future approach to improve the quality of life of patients with nervous injuries. Until now; most functional biomaterials used for this purpose were based on decellularized extra cellular matrix (ECM) or nanofibrous materials, whereas current clinically verified ones in most cases do not exhibit bioactivity or the possibility for external stimulation. The aim of this research was to develop a new type of bioactive, chitosan-based 3D materials applicable as nerve guide conduits (NGCs) modified with poly(dopamine), Au/Pt coated with PVP nanoparticles, and cannabidiol. The NGCs were prepared under microwave-assisted conditions and their chemical structure was studied using the FT-IR method. Next, this study will discuss novel biomaterials for morphology and swelling abilities as well as susceptibility to biodegradation in the presence of collagenase and lysozyme. Finally, their potential in the field of nervous tissue engineering has been verified via a cytotoxicity study using the 1321N1 human astrocytoma cell line, which confirmed their biocompatibility in direct contact studies. Full article

(This article belongs to the Special Issue Recent Advances in Functionalized Nanomaterials: Design, Synthesis, Characterization, and Application)

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