Volume 5 Issue 1, January 2013

The metal cofactors responsible for the activity of CDK2 — a representative member of the kinase superfamily of enzymes — have now been shown to also have inhibitory effects during the catalytic cycle.

Quantum mechanics rears its head in many places and one of them is inorganic chemistry, where the electronic spin associated with unpaired electrons has a profound influence. This was the topic of the 2012 CECAM workshop.

Natural products contain a range of chemical structures optimized for biological interactions. Fragmenting these compounds could help to combine this diversity with the broad coverage of chemical space offered by fragment-based drug discovery, and help to improve the efficiency with which screening hits can become successful drugs.

The biosynthesis of peptidoglycan is an important step in bacterial cell division and cell-wall maturation. Now it has been shown that fluorescent D-amino acids can be used to label the peptidoglycan cell wall of living bacteria, providing a new tool to study this important process.

An experimental set-up has been devised to monitor mechanochemical processes in situ, yielding direct insights into mechanistic and kinetic aspects of solid-state reactions that are promoted by grinding, such as the synthesis of metal–organic frameworks.

A 24 π-electron antiaromatic hexaphyrin derivative (rosarin) with a near-planar geometry enforced by bridging phenylene groups has been shown to undergo a proton-coupled electron transfer reduction when treated with certain protic acids. The reduction proceeds in a stepwise fashion to give first a 25 π-electron non-aromatic system and then a 26 π-electron aromatic ring.

Natural products populate areas of chemical space not occupied by average synthetic molecules. Here, an analysis of more than 180,000 natural product structures results in a library of 2,000 natural-product-derived fragments, which resemble the properties of the natural products themselves and give access to novel inhibitor chemotypes.

The infrared spectra of gas-phase protonated water clusters and protonated liquid water have been calculated from molecular simulations using a ‘clusters-in-liquid’ approach, which is restricted to a selected set of charged atoms. The infrared absorption due to the central proton in the H₂O···H⁺···OH₂ moiety is found near 1,740 cm⁻¹.

The selective dissociation and formation of different functional groups in a single organic molecule may prove useful for making nanoscale devices and offer new opportunities for studying changes in electronic structure. It has now been shown that bond-selective chemistry can be induced and visualized at the submolecular level in a complex thiol-based molecule using a scanning tunnelling microscope.

Supramolecular gels whose properties can be tuned through non-covalent interactions — typically metal coordination or hydrogen bonding — are attracting attention in various fields. Researchers have now shown that halogen bonding is also strong enough to be relied on; it interferes with competitive, gel-inhibitory hydrogen bonding to induce co-gelation between two urea-based components.

Efficient hydrogen-evolving catalysts comprising readily available elements are needed if hydrogen is to be adopted as a clean alternative to fossil fuels. Now, a diimine–dioxime cobalt complex has been covalently attached to a carbon nanotube electrode to yield an active and robust electrocatalyst for hydrogen generation (55,000 turnovers in seven hours) from aqueous solutions.

The in situ trapping of pyridynes is an efficient method for the generation of a variety of substituted pyridines but, until now, the method has been hampered by a lack of regiocontrol. Here, proximal halide and sulfamate substituents are shown to perturb pyridyne distortion and thus govern regioselectivities in pyridyne reactions.

Xenon is an inert element at ambient conditions but may become reactive under pressure. It has now been predicted that pressure stabilizes increasing oxidation states of Xe atoms (from Xe⁰ to Xe²⁺ to Xe⁴⁺ to Xe⁶⁺), and thus a series of compounds — XeO, XeO₂ and XeO₃ — become thermodynamically stable at megabar pressures.

Milling and grinding, long used to alter the chemical and physical properties of materials, have recently garnered interest as alternatives to traditional solution-based syntheses — but these reactions remain difficult to monitor. High-energy synchrotron X-ray radiation has now enabled the in situ observation, in real time, of solid-state transformations occurring during the mechanochemical syntheses of metal–organic frameworks.

Daniel Rabinovich outlines the history, properties and uses of aluminium — one of the most versatile, pervasive and inexpensive metals today, yet it was considered a rare and costly element only 150 years ago.