News & Views in 2015

Electron transfer is ubiquitous across both life and modern technologies, and thus being able to control it is an attractive goal. Now, targeted infrared excitation has been used to modulate the efficiency of electron transfer in a series of donor–bridge–acceptor molecules.

Controlling the site-selectivity of C–H activation reactions is a major obstacle for the development of synthetically useful methodology. Now, meta-C–H functionalizations of arenes have been achieved by exploiting weak secondary interactions of a metal-coordinating ligand with the substrate.

Solid-state perovskite solar cells have recently emerged and have already reached efficiencies of 20%. Now, a simple solution-processing step that crosslinks neighbouring perovskite grain surfaces has been found to increase their stability, an important issue for future potential commercialization.

How complex is it to synthesize a given molecular target? Can this be answered by a computer? Now, a model of synthetic complexity that factors in methodology developments has resulted in a complexity index that evolves alongside them.

A pair of artificial DNA bases have now been shown to adopt an edge-to-edge geometry in DNA which is similar that found in Watson–Crick base pairing. Aptamers containing these bases have also been shown to bind more strongly to a target than those developed using only the four naturally occurring bases.

Hybrid organic–inorganic lead halide perovskites have recently emerged as ground-breaking photovoltaic materials. A recent confocal fluorescence microscopy study now raises hopes that perovskite solar cells can reach efficiencies beyond the recent record of 20%.

Molecules can transfer charge between electron donors and acceptors, and can also transport charge when connected between metallic electrodes. These processes are assumed to show generally similar trends, however, a significant departure from this has now been observed in a series of biphenyl bridges.

Bioorthogonal catalysis provides new ways of mediating artificial transformations in living environs. Now, researchers have developed a nanodevice whose catalytic activity can be regulated by host–guest chemistry.

Deoxygenation reactions have been used to convert biomass-derived carbohydrates into useful platform chemicals. Now, a method has been described that can selectively excise C–O bonds to produce valuable chiral synthons.

An electrochemical clamp assay that enables the rapid and sensitive detection of nucleic acids containing single base mutations has now been developed. It has been shown to differentiate between cancer patient samples featuring a specific mutation, and controls from healthy donors or other cancer patients, all directly in unprocessed serum.

The transfer of chirality is known to occur through chemical bonds. Now, chiral biomolecules have been observed to impart some of their optical properties to a spatially separated achiral dye — with the transfer mediated by plasmon resonance from an achiral metallic nanostructure.

Supramolecular polymerizations typically proceed through stepwise intermolecular mechanisms, concomitant with many side reactions to yield aggregates of unpredictable size, shape and mass. Now, a chain-growth strategy is shown to allow assembly of molecules into supramolecular chain structures endowed with precisely controlled characteristics.

Computations of the energetics and mechanism of the Morita–Baylis–Hillman reaction are “not even wrong” when compared with experiments. While computational abstinence may be the purest way to calculate challenging reaction mechanisms, taking prophylactic measures to avoid regrettable outcomes may be more realistic.

Bulk SiO₂ is widespread in nature, and silicon oxide clusters are important to a variety of applications, yet molecular silicon oxides have remained elusive. Two molecular compounds featuring silicon oxide moieties, Si₂O₃ and Si₂O₄, have now been isolated by oxidation of a carbene-stabilized disilicon precursor.

Incorporating mechanically interlocked molecular shuttles within a metal–organic framework that has enough free space in the crystal lattice to permit volume-conserving translational motion sets the stage for defect-free molecular-electronic device fabrication and more.

Defect-free Sierpiński triangles can be self-assembled on a silver surface through a combination of molecular design and thermal annealing. Three-fold halogen-bonding arrays and precise surface epitaxy preclude structural errors, thus enabling the high-level complexity of these supramolecular fractal patterns.

In 1972, Baird showed theoretically that the electron counting rule for aromaticity and antiaromaticity in the lowest ππ^* triplet state is opposite to that in the electronic ground state. A pair of compounds that manifests this reversal in character has now been identified and characterized experimentally for the first time.

Symbiotic bacteria synthesize many specialized small molecules; however, establishing the role these chemicals play in human health and disease has been difficult. Now, the chemical structure and mechanism of the Escherichia coli product colibactin provides insight into the link between this secondary metabolite and colorectal cancer.

Scaling relations between the molecular structures of reactive intermediates and the strength of the bonds they form with flat surfaces have now been extended to also predict how bonding strength is affected by surface topography. These relations can be applied to design more efficient nanoparticle catalysts.

Analysing post-translational modifications of histone proteins as they occur within chromatin is challenging due to their large number and chemical diversity. A major step forward has now been achieved by using split intein chemistry to engineer functionalized histones within cells.