Articles in 2019

The broad infrared spectrum of water in the OH stretching region shows how significantly a water molecule is distorted when within a hydrogen-bonding network; it also raises the question of what the spectrum of a single OH oscillator would be. Now, the spectral signatures of isolated OH oscillators embedded in cold water cages have been measured using vibrational spectroscopy.

Despite the potential of fluorinated compounds in pharmaceuticals and agrochemicals, the formation of C–F bonds remains challenging. It has now been shown that aryl sulfonium salts, which can be made by site-selective C–H functionalization, have advantageous photoredox reactivity compared to conventional (pseudo)halides and can be used for late-stage C–H fluorination.

High electrical conductivities in metal–organic frameworks—attractive for applications in sensing and energy storage—typically arise in layered MOFs from metal–ligand bonds with strong covalent character. Now, lanthanide-based MOFs have shown high out-of-plane conductivities originating instead from the π-stacking of organic ligands.

Gene-circuit-based sensors have, to date, largely relied on optical proteins (such as green fluorescent protein) to report the output, which limits the signalling bandwidth. Now, an electrochemical output has been developed and integrated with cell-free gene circuits. This approach enables multiplexing of sensors and introduces the possibility of electronic-based logic, memory and response elements to synthetic biology.

Singlet fission produces two low-energy triplet excitons that are difficult to dissociate into free charges. Now, separate optima in charge yield have been observed as a function of driving force for singlet and triplet excitons in pentacene. At optimal driving forces, the triplet-exciton dissociation rate is at least five orders of magnitude smaller than the singlet-exciton dissociation rate.

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.

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.

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.

As the International Year of the Periodic Table draws to an end, we reflect on how it has prompted chemists to explore the past, present and future of this chemical icon.

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.

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.

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.

Despite the regular occurrence of high-profile accidents leading to serious injuries or deaths among lab personnel, the state of academic lab safety research has languished. Existing studies in this area are summarized and critiqued in this Review and suggestions are made for future research directions.

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.

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

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.

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.