Browse Articles

Water has been used in organic synthesis as a hydrogen and oxygen source for reductive and oxidative transformations, respectively. Now water is used as both the source of H₂ and formal oxidant in a ruthenium-catalysed hydrogenative oxidation strategy, enabling the synthesis of lactams from N-heteroarenes in a single synthetic step.

The extraction of urea is an important part of wastewater purification and a potential source of valuable fixed nitrogen. Here the authors combine electrocatalytic oxygen reduction with precipitation of urea from urine in the form of a solid peroxide (percarbamide) and demonstrate several potential applications.

The understanding of electrochemical interfaces between polymer electrolytes and metal electrodes, which is critical to many practical devices, remains limited. Now, the interaction between Nafion’s sulfonate groups and platinum and its impact on the oxygen reduction reaction is studied in detail, and a distinct coupled cation–electron transfer mechanism is identified.

Electrolyte cations have been shown to have a strong impact on reactivity in electrocatalytic CO₂ reduction. However, most studies have been performed in an aqueous environment. Here the effect of various alkylammonium cations on CO₂ reduction in aprotic solvents is investigated, with the interfacial electric field induced by the cations shown to be a dominant factor.

Understanding the interplay between solvent, reactant and catalyst is important to advance towards upgrading biomass into useful products, but the process remains challenging. Now a study on guaiacol demethylation in water highlights the substantial shift in catalytic behaviour that occurs when moving from bulk water to the confined space within zeolite channels.

The efficiency of enantioselective sp³ C–H bond oxidation using small synthetic catalysts is usually limited. Now a catalytic system involving a Cu(II)-bound tert-butoxy radical for site-selective C–H bond cleavage achieves allylic and propargylic sp³ C–H oxidation with the C–H substrates as the limiting reagent.

Methane has been notoriously difficult to activate for useful chemistry. Now, a tandem catalyst system comprising an iron-modified zeolite and an enzyme is developed for the partial oxidation of methane to formaldehyde under ambient conditions using hydrogen peroxide as the oxidizing agent. This approach achieves high selectivity and conversion to formaldehyde.

A catalytic, metal-free method for generating carbanion equivalents has been developed, providing a modern alternative to classical Grignard addition reactions. This approach overcomes the traditional drawbacks associated with the use of stoichiometric amounts of metalated reagents, aligning this strategy with contemporary sustainability requirements.

Conventional thermocatalytic routes to 1,3-butadiene are energy intensive. Now, a method for the selective electroreduction of acetylene to 1,3-butadiene under ambient conditions is demonstrated. Use of an iodide-containing electrolyte stabilizes partially oxidized copper sites on the catalyst, facilitating the synthesis of 1,3-butadiene with a Faradaic efficiency of up to 93%.

Understanding metalloenzymes can inspire the design of molecular catalysts. Employing signal-enhanced nuclear magnetic resonance spectroscopy on parahydrogen-reduced [Fe]-hydrogenase, two reaction intermediates have been characterized. This work paves the way toward a microscopic understanding of these metalloenzymes.

Recent findings on electrocatalysis promoted by alkali metal ions (AM⁺) have challenged the prevailing consensus that AM⁺ are chemically inert spectators. Now, theoretical and experimental evidence of an AM⁺-coupled reaction intermediate contribute to confirming the catalytic role of AM⁺ in electrochemical processes.

Elucidating the nature of the Fe active sites in Fe-zeolite catalysts and the reaction mechanism operating during the concurrent removal of NO and N₂O is very challenging. Now, complementary transient operando spectroscopies are deployed to disentangle the structure and activity of diverse Fe species and elementary reaction steps.

Photoredox catalysis is merged with metalloenzymatic catalysis to enable asymmetric decarboxylative azidation and thiocyanation. These transformations are achieved by coupling the photoredox activation of N-hydroxyphthalimide esters using a synthetic photocatalyst with enantioselective radical capture by Fe(iii) intermediates of non-haem iron enzymes.

Polymer/whole-cell hybrid catalysts were created by synthesizing catalytically active polymers from the surface of Escherichia coli cells that recombinantly expressed enzymes. The surface-engineered bacteria allowed for orthogonal tandem catalysis, involving photo- or chemocatalytic steps by the polymers on the cells and biocatalytic steps by the enzymes within the cells.

In the quest for more efficient and sustainable asymmetric catalytic methods, synthetic organic chemistry has relentlessly explored innovative techniques. This Comment highlights an emerging topic — photoelectrochemical asymmetric catalysis (PEAC) — which fuses molecular photoelectrocatalysis with asymmetric catalysis.

Biocatalysis needs improved reproducibility and quality of research reporting. Our interdisciplinary team has developed a flexible and extensible metadata catalogue based on STRENDA guidelines, essential for describing complex experimental setups in biocatalysis. The catalogue is available online via GitHub for community use.

Decarboxylative azidation is a valuable transformation in organic chemistry, but a biocatalytic equivalent remained elusive. Now merging photoredox with metalloenzymatic catalysis enables the enantioselective decarboxylative radical azidation and thiocyanation of N-hydroxyphthalimide esters.

Alkali cations in electrolytes are commonly considered chemically inert species, but their role has recently been called into question. Now, using in situ spectroscopy and molecular dynamics simulations, it is shown that alkali cations couple with intermediates in the oxygen reduction reaction, acting as cocatalysts.

Proton-exchange membrane water electrolysers often rely on scarce iridium or ruthenium catalysts at the anode, as many low-cost, earth-abundant catalysts cannot withstand the harsh operational conditions. This Review discusses the state of the art in earth-abundant water oxidation catalysts and examines their degradation mechanisms at multiple levels.