Articles in 2022

Inelastic hydrogen atom scattering from surfaces provides a good benchmark for the validity of the Born–Oppenheimer approximation in surface chemistry. Now it has been shown that hydrogen atoms colliding with a semiconductor surface can efficiently excite electrons above the surface bandgap, representing a clear example of the failure of the approximation.

Modulation of surface properties and functions can be achieved through covalent and non-covalent molecular binding, but the lack of responsiveness and requirement for specific binding groups makes spatiotemporal control challenging. Now, it has been shown that adaptive insertion of a hydrophobic anchor into a poly(ethylene glycol) host is an effective non-covalent binding strategy for programmable surface functionalization.

Abhik Ghosh explores the structure, chemistry and applications of corroles, a class of sterically constrained macrocyclic tetrapyrroles.

Methods to access organofluorine compounds with a trifluoromethyl- and fluoro-substituted carbon stereogenic centre are severely limited. Now, a flexible and stereodivergent approach has been developed for the efficient preparation of homoallylic alcohols containing this moiety. Conversion to polyfluoro furanosides and pyranosides has been demonstrated, which is relevant to antiviral drug development.

The facile release of corrosive HCl gas and plasticizers from poly(vinyl chloride) (PVC) makes it a challenging material to recycle. Now, it has been shown that PVC waste can be directly used as a halogen source to synthesize chloroarenes. This paired electro(de)chlorination is mediated by a phthalate plasticizer already contained in PVC waste.

Expanding the biocatalysis toolbox for C–N bond formation is of great value. Now, a biocatalytic amination strategy using a new-to-nature mechanism involving nitrogen-centred radicals has been developed. The transformations are enabled by synergistic photoenzymatic catalysis, providing intra- and intermolecular hydroamination products with high yields and levels of enantioselectivity.

Iodic acid (HIO₃) forms aerosols very efficiently, but its gas-phase formation mechanism is not well understood. Atmospheric simulation chamber experiments, quantum chemical calculations and kinetic modelling have now revealed that HIO₃ forms as an early iodine oxidation product from hypoiodite. The mechanism explains field measurements and suggests a catalytic role for iodine in particle formation.

Gold nanoparticles typically exhibit hard-sphere-like assembly behaviour, but now the size, morphology and symmetry of crystals of Au₂₅ nanoparticles have been tuned. The presence of excess tetraethylammonium cations has been shown to promote the one-dimensional assembly of the nanoparticles, which in turn form rod-like crystals, by stabilizing dynamically detached ligands from adjacent particles into interparticle linkers through CH⋯π and ion-pairing interactions.

Native mass spectrometry has been used to interrogate both biased signalling and allosteric modulation of the β₁-adrenergic receptor. Simultaneously capturing the effects of ligand binding and receptor coupling to different G proteins has enabled the relative importance of specific interactions to be investigated.

Kinetic isotope effect studies can provide valuable insights into the complex mechanisms of the oxygen reduction reaction; however, inaccessibility to ultra-high-purity D₂O has made this difficult. Now, a methodology to prepare ultra-pure D₂O has been developed and inverse kinetic isotope effects have subsequently been measured for the oxygen reduction reaction on platinum single-crystal surfaces, providing mechanistic insights.

The direct carbon isotope exchange reaction on α-amino acids is highly desirable, as existing labelling methods require several synthetic steps and harsh conditions. Now, an aldehyde-catalysed carboxylate exchange with isotopically labelled *CO₂ has enabled the direct formation of ¹¹C, ¹³C and ¹⁴C-labelled α-amino acids.

The study of rare isotopes, including many in the f-block, is a key step to advancing our fundamental understanding of these elements, but their scarcity poses challenges. Now, minute amounts of such materials have been isolated and characterized through complexation with polyoxometalate clusters.

Geminal disubstitution of cyclic monomers is known to improve the chemical recyclability of their polymers, but usually at the expense of performance properties. Now, geminal disubstitution of a six-membered lactone has been shown to synergistically enable chemical recyclability back to the monomer and enhance the materials performance of the resulting polyesters, with properties that rival or exceed those of polyethylene.

Incorporating silicon into organic molecules and materials leads to interesting changes in electronic structure and properties; silabenzenes are attractive species for this purpose, but their high reactivity in solution poses challenges. Now, 1D and 2D covalent organic frameworks featuring disilabenzene rings (C₄Si₂) as linkers have been prepared by reacting silicon atoms and polyaromatic hydrocarbon precursors on a Au(111) surface.

Carbon-labelled α-amino acids are valuable compounds in drug development and nuclear medicine, but are difficult and time consuming to prepare. Now, an aldehyde-catalysed method has been developed for the direct C1-labelling of α-amino acids using *CO₂ (* = 14, 13, 11), providing access to many proteinogenic and non-natural labelled α-amino acids.

The circadian rhythm generates out-of-equilibrium metabolite oscillations controlled by feedback loops under light/dark cycles. Now, it has been shown that these life-like properties can emerge from a non-equilibrium nanosystem comprising a binary population of enzyme-containing polymersomes capable of light-gated chemical communication, controllable feedback and coupling to macroscopic oscillations.

Heavy analogues of carbynes of the type R–\({{{\dot{\mathrm E:}}}}\), where E is a group 14 element, are difficult to isolate in the condensed phase due to their high reactivity. Now, a germylyne radical supported by a sterically hindered hydrindacene ligand has been prepared and structurally characterized. Theoretical calculations show that the spin density mainly resides at the germanium centre.

Despite recent advances in engineering of in vitro translation systems, direct ribosomal incorporation of hydroxyhydrocarbon moieties—which can endow peptides with unique biochemical/folding properties—remains challenging. Now, incorporation of translation-compatible azide/hydroxy acids and their post-translational tandem backbone-acyl shifts have enabled in vitro ribosomal synthesis of peptides containing various hydroxyhydrocarbon units.

Identifying and quantifying the biodistribution of synthetic polymeric nanoparticles in biological milieu is crucial for biomedical applications. Now, it has been shown that encoded polymeric amphiphiles with discrete molar masses undergo sequence- and length-dependent self-assembly into precise digital micelles that can be used in direct sequence reading and ex vivo label-free quantification assays.

Enteropeptins are peptide natural products produced by the gut microbe Enterococcus cecorum. Now, the structure, biosynthesis and function of enteropeptins have been determined. After ribosomal biosynthesis, enteropeptins are post-translationally modified in three reactions carried out by a radical S-adenosylmethionine enzyme, an Mn²⁺-dependent arginase, and an Fe–S-containing methyltransferase, respectively, to form the N-methylornithine-containing peptide natural products.