Volume 14 Issue 1, January 2022

Bilayer borophene, predicted to be stabilized by interlayer linkages, has now been grown by molecular beam epitaxy on copper and silver surfaces in two independent studies. The growth substrate and temperature are found to influence the lattice structures formed.

Membraneless coacervate droplets have been widely investigated as potential candidates for early cells or protocells. Now, they are shown to grow, divide and differentiate into two populations in a rock pore model that mimics an early Earth environment.

It is extremely difficult to design a broad-spectrum inhibitor for metallo-β-lactamases (MBLs) due to the diversity in the active site. Now, indole-2-carboxylates have been developed as broad-spectrum inhibitors for MBLs. These inhibitors take advantage of key elements of both MBL substrates and products and work by locking a hydroxide.

Why do bulky anions solubilize macromolecules in water but precipitate out the corresponding monomers? The answer lies in the differences in local water structure. Polymers have now been shown to disrupt water structure more than their monomers, leading to an accumulation of anions near the polymers that increases their solubility.

Innovations in instrumentation together with new strategies of data collection and processing have been shown to solve the problem of data quality for time-resolved in situ X-ray diffraction studies on ball milling, opening new horizons in mechanochemistry.

Dinitrogen conversion to ammonia is of great biological and industrial relevance, but modelling this process on a molecular level is challenging. Now, a biomimetic model offers new insights into the functionalization of a nitrido ligand to form NH₃ using either H₂ or H⁺/e^–.

The efficacy of carbapenem antibiotics can be compromised by metallo-β-lactamases, but a high-throughput screen followed by optimization has now enabled the discovery of indole-2-carboxylates (InCs) as potent broad-spectrum metallo-β-lactamase inhibitors. The results highlight the potential of InC–carbapenem combinations for clinical use as well as mechanism-guided approaches to combatting globally disseminated antibiotic resistant mechanisms.

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.

Complex coacervate microdroplets have been proposed as primordial cells, but their ability to evolve by fusion, growth and fission has not yet been demonstrated. Now, it has been shown that gas bubbles inside heated rock pores can drive the growth, fusion, division and selection of coacervate microdroplets.

Weakly hydrated anions solubilize macromolecules but cause small molecules that are made from identical chemical constituents to precipitate out of aqueous solutions. Now, this phenomenon has been understood by demonstrating that the binding of anions to polymers is regulated by molecular curvature and interfacial water structure.

Multi-iron nitrides are implicated as potential key intermediates in biological nitrogen fixation and the industrial Haber–Bosch process, but well-described functional model systems are rare. Now, a well-defined thiolate-bridged Fe^IVFe^IV μ-nitrido complex has been found to show excellent reactivity toward hydrogenation with H₂ through a stepwise pathway to form ammonia in high yield.

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.

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.

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.

Strategies for the selective modification of heteroatom-containing aromatic compounds are in high demand. Using a simple pyrylium reagent and a cheap chloride source, a method has now been developed that can selectively replace NH₂ groups attached to heteroaromatic rings with a chlorine atom to give heteroaryl chlorides.

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.

Direct coupling methods, which do not require substrate prefunctionalization, are highly desirable for the construction of complex molecular scaffolds. Now, a photochemical method has been developed for the direct decarboxylative coupling of carboxylic acids with diverse nitrogen, oxygen and carbon nucleophiles, taking advantage of the photochemistry of copper(II) carboxylate complexes assembled in situ.

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.

John Woodland and Kelly Chibale retrace the tumultuous history of quinine from a medicine — used as a tool for colonialism — to a puzzling chemical target, a fluorescence standard and a key ingredient in popular drinks.