Articles in 2017

Mathematically modelling metal–ligand bonding in late transition-metal complexes has been an important tool in catalyst development — although lacking for early transition metals such as Cr and Ti. Now, a simple method for measuring ligand donor properties promises to elevate high-valent early transition metal catalysis to the same level.

Merging the advantages of homogeneous and heterogeneous catalysts is a useful strategy for creating improved catalytic systems. Now, a concept has been developed that uses single Pd atoms — supported within liquid alloy droplets — that emerge from the droplet subsurface and interior to react with molecules approaching from the gas phase.

Suzanne Bart from Purdue University talks to Nature Chemistry about her investigations into the chemistry of actinides, and why she finds them both challenging and rewarding.

Our understanding of actinide chemistry lags behind that of the rest of the periodic table. A collection of articles in this issue highlights recent progress featuring uranium(VI) dianions bearing four U–N multiple bonds, berkelium(IV) stabilized in solution and delocalization of 5f electrons in a plutonium material.

Two coordination cages have been devised that undergo covalent modification during a cascade of two orthogonal Diels–Alder reactions. This results in increased lipophilicity for the second cage, enabling its phase transfer and separation from the first. The trigger, relay and inhibition features of this cascade system mimic key aspects of natural post-translational modification cascades.

Despite advances in peptide synthesis techniques, explicit control over the quaternary structure of synthetic peptides has remained elusive. Now, the dynamic covalent chemistry of hydrazide- and aldehyde-containing peptides has now been shown to enable the formation of unique quaternary structures with topological diversity. Using this method, oligomers were assembled into complex structures showing dramatic enhancements of antimicrobial effectiveness versus Staphylococcus Aureus.

The first demonstration of a protein designed entirely from first principles that binds a small-molecule cofactor in a precisely predetermined orientation has now been described. The design method utilizes a remote protein core that both anchors and predisposes a flexible binding site for the desired cofactor-binding geometry.

Chemically termolecular reactions — arising from the collision of ephemeral collision complexes with other chemically reactive species — have been neglected in current gas-phase chemical mechanisms of combustion and planetary atmospheres. First-principles calculations reveal that such chemically termolecular reactions constitute major pathways affecting macroscopic observables.

Intercalation — a cornerstone of materials science with wide-ranging applications — has now been demonstrated in a superatomic crystal. A redox-active tetracyanoethylene guest was inserted into the lattice of a material consisting of alternate layers of {Co₆Te₈} clusters and C₆₀ fullerenes, leading to a single-crystal-to-single-crystal transformation that significantly modulates the material's optical and electrical transport properties.

Polyoxygenated aliphatic chains with multiple hydroxyl groups are common in a wide array of compounds, often with potent biological activity. Now, a new ruthenium catalyst enables selective dehydrogenation of a single hydroxyl group in a broad scope of complex polyols. This site-selective modification facilitates the rapid incorporation of nitrogen-based functional groups into diverse natural products.

Interest in surface-mediated chemistry has led to the design of small molecule models for surfaces, which provide mechanistic insight and have practical applications. Now, the cooperative behaviour of five nickel centres has been shown to provide reactivity reminiscent of highly active metal surface sites, leading to carbon-atom abstraction from alkenes under ambient conditions.

Although samarium-mediated cyclizations have the potential to generate significant molecular complexity, historically it has not proven possible to exert enantiocontrol through the use of a chiral ligand in complex product synthesis. Now, an enantioselective SmI₂-mediated radical cyclization has been developed using a chiral aminodiol ligand. Desymmetrizing 5-exo ketyl-alkene cyclizations and cyclization cascades of unsaturated ketoesters deliver complex products and typically proceed with high enantioselectivity and diastereoselectivity.

Catalysis involving high-valent metals is an important facet of modern chemistry, but tools for catalyst development in this field have lagged behind those for low-valent systems. Now, an experimental system that can accurately model and predict reactivity has been developed to aid high-valent catalyst design.

Mononuclear gold(II) complexes are very labile (and thus very rare) species. Now, a gold(II) porphyrin complex has been isolated and characterized, and its reactivity towards dioxygen, nitrosobenzene and acids investigated. Owing to a second-order Jahn–Teller distortion, the gold atoms were found to adopt a 2+2 coordination mode in a planar N₄ environment.

Realization of the bicyclic aromaticity has attracted much attention because of the potential to modulate the fundamental properties of 3D aromatic organic molecules that are not topologically planar. Now, the synthesis and characterization of dual-aromatic molecules, and their electronically mixed [4n+1]/[4n+1] triplet bi-radical species displaying Baird-type aromaticity, has been realized.

A chemical proteomic strategy has now been reported for the global profiling of lysine reactivity and ligandability. Using this approach, >9000 lysines in the human proteome were evaluated, leading to the discovery of hyper-reactive lysines, and lysines that can be targeted by electrophilic small molecules to perturb enzyme function and protein–protein interactions.

Delayed resolution of G-quadruplexes during replication can induce localized loss of epigenetic information and changes in gene expression. Now, this effect has been used to discover biologically potent G-quadruplex ligands and to demonstrate that G-quadruplex stabilization can induce epigenetic changes that are heritable across cell divisions even after the ligand is removed.

Bacterial naphthoquinone meroterpenoid natural products defy biosynthetic logic via classical biochemical paradigms. Now, an enzyme promoted α-hydroxyketone rearrangement catalysed by vanadium-dependent haloperoxidases reveals a conserved biosynthetic reaction in this molecular class that further has inspired a concise biomimetic synthesis of naphthomevalin, a prominent member of the napyradiomycin meroterpenes.