Volume 3 Issue 2, February 2011

Nature reduces dinitrogen under mild conditions using nitrogenases, the most active of which contains molybdenum and iron. The only abiological dinitrogen reduction catalyst that avoids the harsh conditions of the Haber–Bosch process contains just molybdenum.

One-electron oxidation is generally expected to weaken a bond in a molecule or, on rare occasions, break it. Removing one electron from a small propellane cage has now been shown to break three lateral bonds, opening it up into an acyclic cation after a cascade of rearrangements, initiated by vibronic coupling.

The radical–radical association reaction between hydroxyl and nitrogen dioxide plays a central role in atmospheric chemistry but has challenged experimentalists for decades. A study now measures all reactants and products and largely settles the issue.

An unusual cyclization reaction to form alkylarenes — which are important chemical feedstocks — from alkanes is mediated by an iridium catalyst.

The programmable and reliable hybridization of DNA strands has enabled the preparation of a wide variety of structures. This Review discusses how, in addition to these static assemblies, the process of displacing — and ultimately replacing — strands also makes possible the construction of dynamic systems such as logic gates or autonomous walkers.

Metalloporphyrins have a variety of roles in nature, including catalysis and the transport of respiratory gases, and many of these involve the binding of diatomic molecules. Now, the interaction of carbon monoxide with simple iron- and cobalt-porphyrins has been studied at the single-molecule level, revealing a surprising binding scheme.

Nitrogen fixing is an extremely energy-consuming industrial process so there is much effort underway to develop better catalytic methods. Now, a dimolybdenum–dinitrogen complex bearing a PNP pincer ligand has been found to work as an effective catalyst for the formation of ammonia from dinitrogen.

Although most proteins fulfil their role as part of large protein complexes, little is known about the pathways of complex assembly. Here, ion mobility–mass spectrometry is used to monitor and structurally characterize the assembly intermediates of viral protein shells, called capsids, of two major human pathogens, norovirus and hepatitis B virus.

Organic aerosol particles are important to climate and human health but remain poorly characterized on account of their immense chemical complexity. Here, using both field and laboratory measurements of organic aerosol, we demonstrate the use of average carbon oxidation state for describing aerosol chemical properties and atmospheric transformations.

Visible light photoredox catalysis has emerged as a powerful technique for chemoselective activation of chemical bonds under mild reaction conditions. Here, visible-light-mediated conversion of alcohols to the corresponding bromides and iodides is described. The reaction proceeds in good yield with exceptional functional group tolerance, and minimizes the formation of stoichiometric waste.

A DNA-encoded reaction discovery system has revealed reactivity that led to the development of a visible-light-induced, biomolecule-compatible azide reduction. This reaction exhibits remarkable chemoselectivity and can be performed on oligonucleotide and oligosaccharide substrates, and in the presence of a protein enzyme, without undesired side reactions or loss of enzyme activity.

Characterization of plasma membrane proteins is important in understanding fundamental biological processes and developing new drugs, but their separation remains a challenge. Now, a synthetic receptor–ligand pair based on ferrocene derivatives and cucurbit[7]uril is shown to have exceptionally high binding affinity, and enables membrane proteins to be isolated efficiently without any contamination from naturally biotinylated molecules.

Developing efficient thermoelectric materials that can directly generate electrical power from heat is a challenge, but now a nanostructured system of SrTe nanocrystals in a Na₂Te-doped PbTe matrix achieves high efficiency by blocking heat flow without impeding carrier flow.

Aromatic hydrocarbons are among the most important building blocks in the chemical industry. Here, n-alkanes are catalytically converted to alkylaromatics, in yields up to 86%, using ‘pincer’-ligated iridium complexes and olefinic hydrogen acceptors. The carbon number of the n-alkanes is retained in the products, which are exclusively unbranched (n-alkyl-substituted).

Amyloid cascades leading to peptide β-sheet fibrils are central to many diseases. Intermediate assemblies were recently identified as the toxic agents, but obtaining structural details of these early oligomers has largely been unsuccessful with traditional techniques. Here, ion mobility methods provide evidence for structural transitions from random to β-sheet assembly.

Katharina M. Fromm explains how, as well as catalysis and jewellery, silver serves a myriad of medicinal applications — some of which are even behind poetic traditions such as throwing coins in wishing wells.