Articles in 2021

The synthesis of chiral interlocked molecules in which the mechanical bond provides the only source of stereochemistry remains challenging. Now, a chiral interlocked auxiliary approach to mechanically planar chiral rotaxanes has been developed and its potential demonstrated through the synthesis of a range of difficult targets with high enantioselectivity.

The contributions of chirality and conformation as contributing factors to the biological properties of synthetic nanomaterials remain underexplored. A synthesis of bottlebrush polymers with mirror-image side chains has now been developed and it has been revealed that an interplay between side-chain absolute configuration and flexibility influences the biological properties of these polymers both in vitro and in vivo.

Five-membered lactones are common in nature and are produced in large quantities from biomass, but a lack of ring strain means that ring-opening polymerization is usually thermodynamically unfavourable at ambient conditions. Now, an irreversible ring-opening polymerization of biomass-derived five-membered thionolactones—driven by S/O isomerization—has been developed, enabling their conversion into sustainable polymers at industrially relevant temperatures.

Medium-chain linear α-olefins are commodity chemicals; however, manufacturing α-olefins from biomass is challenging due to inefficient removal of the last oxygen atoms. Now, a two-step biological–chemical catalysis strategy to produce medium-chain linear α-olefins provides a route to sustainable polymers.

Atmospheric chemists have been unable to explain the rapid sulfate formation observed during wintertime aerosol pollution events. Now, kinetic measurements in atmospherically relevant aerosol particles have highlighted a significant role for nitrogen dioxide in sulfate formation via its interfacial reaction with dissolved SO₂.

Jennifer Leigh and Jennifer Hiscock, both from the University of Kent, UK, share with Nature Chemistry the origins of the Women In Supramolecular Chemistry (WISC) network, as well as some of the projects underway to try to help change the culture of this area of chemistry from the bottom up.

Early-career researchers have been particularly impacted by the COVID-19 pandemic. To re-assemble the supramolecular research community, the inaugural Women in Supramolecular Chemistry workshop promoted a community-led approach to skills development, as Ruhee Dawood and Alyssa-Jennifer Avestro recount.

A protein–nanopore machine that can unfold, thread and degrade a protein has now been developed. Fabricated in a bottom-up fashion, the nanopore machine is assembled from three proteins and provides an important step towards deciphering the sequence of single proteins via nanopores.

A dual cellular-then-heterogeneous catalysis strategy has been used to produce olefins from glucose. 3-Hydroxy acids are made using an engineered microbial host. A hydrolytic step then provides the driving force for fatty acid deoxygenation by simple heterogeneous Lewis acid catalysis. This decarboxylation–dehydration route to olefinic products avoids the need for an additional redox input typically required for deoxygenation of unmodified fatty acids.

Degradable polymers are important for technological applications and sustainability, but they remain difficult to access via ring-opening metathesis polymerization (ROMP). Now, commercial 2,3-dihydrofuran is shown to be an effective ROMP comonomer for various norbornenes. This copolymerization generates new acid-degradable polymers with controlled molecular weights, different functionalities and tunable properties.

An integrated multiprotein nanopore has been fabricated using components from all three domains of life. This molecular machine opens the door to two approaches in single-molecule protein analysis, in which selected substrate proteins are unfolded, fed to into the proteasomal chamber and then processed either as fragmented peptides or intact polypeptides.

The systemic discovery of metal–small-molecule complexes from biological samples is a difficult challenge. Now, a method based on liquid chromatography and native electrospray ionization mass spectrometry has been developed. The approach uses post-column pH adjustment and metal infusion combined with ion identity molecular networking, and a rule-based informatics workflow, to interrogate small-molecule–metal binding.

Electron spin resonance spectroscopy has traditionally been used to study large ensembles of spins, but its combination with scanning tunnelling microscopy recently enabled measurements on single adatoms. Now, individual iron phthalocyanine complexes adsorbed on a surface have been probed. Their spin distribution partially extends on the phthalocyanine, leading to a strong geometry-dependent exchange coupling interaction.

Several polymorphs of borophene have been synthesized on metal substrates, but typically as monolayers. Now large-size, single-crystalline bilayer borophene has been grown on Cu(111)—a sufficient electron provider to enable the bonding of the second boron layer. The resulting bilayer possesses a metallic character and is less susceptible to oxidation than its monolayer counterpart.

The use of ammonia as an alternative fuel relies on its electrochemical conversion to dinitrogen in a fuel cell. Now a stable metal–metal bonded diruthenium complex is shown to spontaneously produce dinitrogen from ammonia under ambient conditions and is also able to electrocatalyse the oxidation of ammonia to dinitrogen at low potentials.

A conjunctive olefination between aldehydes and carboxylic acids has been developed by merging photoredox catalysis with the Wittig reaction. The process uses a readily available phosphonium salt to join together complex molecular fragments with high functional group tolerance and minimal use of protecting groups, enabling access to coupling products with user-defined geometries.

Biosynthesis of aromatic amines typically uses glutamic acid or glutamine as the nitrogen donor. Now, a biosynthetic pathway to aromatic amines has been reported that uses glycyl-tRNA as the nitrogen donor. The myosin-targeting ammosamide is made via a pathway that involves the post-translational modification of a tryptophan, which is added to the end of a peptide in a tryptophanyl-tRNA-dependent step.