Volume 2 Issue 11, November 2019

Enzymes require many, often hundreds, of amino acid residues arranged in a protein fold to promote catalysis. Now, self-assembly of a single amino acid — phenylalanine — in the presence of zinc is shown to form supramolecular structures that promote hydrolysis better than natural enzymes on a weight basis.

Fusion systems have been designed that link enzymes to cofactors and immobilization modules through appropriate synthetic spacers. These modular biocatalysts (assembling catalysis, cofactor provision/regeneration and assisted immobilization) are suited to heterogeneous biocatalysis systems and can be efficiently used in continuous flow reactors.

Bio-inspired by cellular respiration, the richness of oxygen redox chemistry is a cutting-edge field for building lithium batteries. While the Li–air battery uses external oxygen, a new lithium battery offers a high energy-density and long-term cycling stability just by confining oxygen and lithium between graphene oxides.

Methods to control the performance of heterogeneous catalysts are extremely relevant to the success of industrial processes. This review provides a rationalization of the effects that metal support interactions have on the reactivity of different catalytic systems, emphasizing strategies to tune such effects.

The energies of the species in a given reaction network are linked by linear scaling relationships, limiting the design of catalysts with improved activity and selectivity. In this Perspective, López and Pérez-Ramírez discuss strategies to circumvent such scaling relationships.

Simple enzyme mimetics are highly desired for industrial settings providing high catalyst stability and low production costs. This work reports that phenylalanine and zinc ions can self-assemble into a supramolecular structure showing catalytic properties similar to those of the natural enzyme carbonic anhydrase.

Multi-modal approaches to simultaneously characterize different aspects of a reaction in situ are not readily accessible. Here, catalyst extrudates equipped with both luminescence thermometry and Raman spectroscopy sensors are introduced, providing an in-depth picture for the conversion of syngas on a supported rhodium catalyst.

Asymmetric routes for the formation of tetrasubstituted allenes are scarce and limited in scope. Now, a catalytic asymmetric process is reported giving access to tetrasubstituted allenes from readily available propargylic alcohols, and a potential role for an achiral supporting ligand is postulated.

Tackling the loss of expensive cofactors is a key challenge in continuous-flow biocatalysis. This work reports immobilized enzymes with a tethered cofactor that is channelled between a recycling and a catalysis module facilitating total turnover numbers of NAD⁺ and ATP exceeding 10,000 in biocatalytic flow systems.

Selective functionalization of C(sp³)–H bonds is difficult in alkanes and other hydrocarbons, and especially so for enantioselective reactions. Here the authors report a photocatalyst and chiral metal catalyst to allow the radical, asymmetric addition of alkyl, allylic and benzylic groups to imines.

Visualizing catalysts at work poses significant experimental challenges. Here, an operando scanning tunnelling microscopy study of the cobalt-catalysed Fischer–Tropsch synthesis is presented, which establishes steps as the active sites of the process by correlating activity under realistic conditions with step density.

Lithium-ion batteries exhibit high theoretical gravimetric energy density but present a series of challenges due to the open cell architecture. Now, Zhou and co-workers confine the reversible Li₂O/Li₂O₂ interconversion into a sealed cell by pre-embedding Li₂O nanoparticles into an iridium–graphene catalytic host.

This work shows that the biosynthesis of the polyether tetronasin involves an apparent enzyme-catalysed inverse-electron-demand hetero-Diels–Alder reaction to form an unexpected oxadecalin intermediate. A second enzyme then rearranges the oxadecalin to form the four-ringed tetronasin.