Volume 11 Issue 12, December 2019

Very few consumers are aware that chemistry and synthetic chemicals are indispensable in making everyday goods because the products that people buy — such as cell phones, cars and processed foods — are typically far removed from the raw chemicals used in their production.

Jadambaa Khuyagbaatar from the Helmholtz Institute Mainz and the GSI Helmholtz Centre for Heavy Ion Research talks to Nature Chemistry about superheavy element studies and why creating and exploring these fleeting nuclei matters.

Flavin-dependent halogenases catalyse the regioselective formation of carbon–chlorine and carbon–bromine bonds using oxygen and inorganic halide salts. Now, genome mining has led to the discovery of a previously unknown viral halogenase that catalyses the iodination of arenes, thereby providing a rare biocatalytic tool for the formation of carbon–iodine bonds.

Hydrogen-bonded organic frameworks can readily encapsulate native enzymes and keep them active beyond biological conditions.

Biological receptors distinguish between S- and R-enantiomers and these subtle differences in chirality can lead to vastly different protein affinities. Now, a proteomics approach has been developed that capitalizes on chirality to map enantiomeric probe pairs and provides a rapid and global view of protein ligandability within the cell.

The Catellani reaction is a multi-component cascade sequence, catalysed by palladium and norbornene, which typically uses aromatic starting materials. Now, through the use of a modified norbornene co-catalyst, the scope of this reaction has been extended to alkenyl reagents, enabling the preparation of all-carbon tetrasubstituted olefins.

Nitrogen oxides are major air pollutants; capture and abatement technologies exist but they typically involve toxic species or precious-metal catalysts. Now, a metal–organic framework has been shown to store NO₂ dimers selectively, and to separate NO₂ from other gases under wet conditions. Treatment with water in air leads to conversion of NO₂ into HNO₃—an important feedstock for fertilizer production—with full recovery of the host.

A flavin-dependent halogenase with a remarkable preference for iodination has now been discovered. The halogenase (VirX1) was discovered using a bioinformatics-based approach and comes from a cyanophage. Structural characterization and kinetic studies show that VirX1 possesses broad substrate tolerance, making it an attractive tool for synthesis.

Generating stable single-atom catalysts is far from straightforward and can involve complicated preparation procedures. Now, mononuclear gold oxo-clusters formed in alkaline solutions through a facile one-pot synthesis are shown to catalyse the heterogeneous methanol self-coupling reaction to methyl formate and hydrogen. The intrinsic activity is the same for both supported and unsupported gold catalysts.

All-carbon tetrasubstituted olefins are challenging to prepare in a regio- and stereocontrolled fashion. Now, using an amide-substituted norbornene as a co-catalyst, alkenyl halide- or triflate-mediated palladium/norbornene (Pd/NBE) catalysis has been demonstrated, providing an efficient strategy for modular and regioselective construction of all-carbon tetrasubstituted olefins.

A set of enantioprobes—photoreactive, clickable fragment pairs differing only in absolute stereochemistry—have been used to provide a robust and streamlined chemical proteomic map of small-molecule/protein interactions in human cells. More than 170 stereoselective fragment–protein interactions were discovered and shown to occur at functional sites on proteins from diverse classes.

Ring-opening metathesis polymerization of norbornene-based (macro)monomers produces macromolecules with diverse compositions and complex architectures that cannot be degraded easily. Now, it has been shown that a class of eight-membered cyclic bifunctional silyl ether-based monomers copolymerize efficiently with norbornene-based (macro)monomers, providing a range of copolymers with tunable degradability under mildly acidic aqueous conditions.

Phase-forming conversion chemistry, like that observed in Li–S and Li–O₂ batteries, shows great promise, but these systems suffer some drawbacks, such as practically low cathode areal capacities and electrolyte decomposition. Now, high-energy conversion battery chemistry—based on nitrate/nitrite redox where one of the products is soluble—has been enabled by using nanoparticulate Ni/NiO electrocatalysts.

The isoelectronic series of alanes [R₃Al] and silylium cations [R₃Si]⁺ has now been extended with the synthesis and characterization of two phosphorandiylium dications ([R₃P]²⁺), which are trigonal planar Lewis superacids. The electrophilicity at the phosphorus atom is governed by the π-electron-donating ability of the attached N-heterocyclic imine substituents.

Replacing rare elements in benchmark photosensitizers with iron would facilitate the large-scale implementation of solar energy conversion, but iron complexes generally do not exhibit sufficiently long-lived photoexcited states. Now, it has been shown that iron(ii) complexes with carefully designed ligands can absorb broadly across the visible light spectrum and have charge-transfer excited states with nanosecond lifetimes.

A solution-processing step has been used to prepare quantum-well structures that comprise a thin layer of perovskite sandwiched between two layers of conjugated oligothiophene derivatives. The band gap of the resulting 2D hybrid perovskites can be fine-tuned by functionalizing the organic component, which also improves the stability of the system.

Asymmetric Sonogashira C(sp³)–C(sp) couplings provide complementary approaches to established C(sp³)–C(sp²/sp³) couplings for chiral C–C bond formation; however, relatively few reactions have been developed. Now, a versatile, enantioconvergent Sonogashira coupling via a radical intermediate has been developed. The approach uses a copper catalyst featuring a multidentate electron-rich cinchona alkaloid-derived ligand.