Reviews & Analysis

The behaviour of molecules in confined environments is typically studied in synthetic systems by trapping them inside molecular cages or porous materials. Now, the properties of photosensitive metal–diimine complexes incorporated in the scaffold of a metal–organic framework, rather than in its cavities, have been investigated.

The active sites of enzymes have been widely used as the inspiration for the preparation of self-assembled catalysts. This Perspective describes a more recently adopted approach to catalyst assembly that makes use of the same interactions, but takes its inspiration from more traditional organometallic and organocatalytic approaches.

Interlocking molecules in solution usually requires recognition motifs that direct the assembly of the building blocks. Triply interlocked catenanes have now been constructed just relying on the interpenetration of structures typical of the solid state and slow reversible covalent bond formation.

A photo-reversible metal–semiconductor phase transition can be induced in a nanocrystalline transition-metal oxide at room temperature by short-wavelength light irradiation, holding promise for the development of new optical storage media.

The plant-derived sesquiterpene englerin A is a potent inhibitor of several renal cancer cell lines. Two recent total syntheses have utilized cationic gold(I)-complexes to coax readily available open-chain precursors into englerin's challenging oxotricyclic core with enzyme-like precision.

A systematic study that combines both theory and experiment now provides direct evidence for the existence of anion–π interactions in compounds that facilitate the transport of anions across phospholipid membranes. This study offers new insight into the factors that affect the strength, selectivity and functional relevance of anion–π interactions.

Olefin metathesis is a flexible and efficient method for making carbon–carbon bonds and has found widespread application in academia and industry. Now, a detailed mechanistic study looking at key catalytic intermediates offers new insight into this reaction, and may prove useful in the development of more active and selective catalysts.

Ethers — such as the widely used tetrahydrofuran — are mostly known in chemistry labs as inert solvents. A bimetallic base has now been shown to dismember this simple cyclic ether, breaking six of its bonds and capturing all the atoms in quantitative products.

The cell's dynamic skeleton, a tightly regulated network of protein fibres, continues to provide inspiration for the design of synthetic nanostructures. Genetic engineering has now been used to encode non-biological functionality within these structures.

Sunlight is potentially an ideal green 'reagent' for chemical synthesis, but poor absorption by organic substrates makes direct solar photochemistry generally inefficient. Here, recent progress in the use of the simple organometallic complexes to harness the power of the sun is summarized, and prospects for the future of this exciting field highlighted.

The absorption of a single photon can cause the excitation of more than one electron, but the mechanism of this 'multi-exciton generation' process is elusive. Now, calculations on pentacene show that geometrical distortions and intermediate excited states assist in producing two excited electrons from one photon.

Can two identical reactors with the same concentrations, under identical physical conditions, have reaction rates that differ by a factor of a thousand? A study now shows that, although not true in uncrowded environments, a reactant's starting point makes a large difference to reaction kinetics in identically crowded systems, such as cellular nuclei.

Ultrasound can be used to control molecular processes as delicate as rotation around a single carbon–carbon bond.

Mechanical linking of small cage structures leads to a type of metal–organic framework with an architecture topologically distinct from those constructed so far.

Controlling the movements of molecular systems through external stimuli is crucial for the construction of nanoscale mechanical machines. A spring-like compound has now been prepared — a double helicate that retains its handedness under ion-triggered extension and contraction.

Despite knowing that the active centres of many metalloprotein enzymes are iron porphyrin 'haem' complexes, chemists find them difficult to imitate. Now, the assembly of haem-like centres into a crystalline, stable, nanoporous array shows promise for biomimetic catalysis.

The composition of dynamic small-molecule libraries can be biased by the addition of a target compound — such as a protein — that binds selectively to one of the components in the mixture. The chemistry of the library must, however, be compatible with the target and it has now been shown that aniline-catalysed exchange of acylhydrazones fits the bill.

The catalytic reduction of atmospheric N₂ to NH₃ under mild conditions is one of the challenges of organometallic chemistry. An iron-based complex that binds and activates N₂ has now been developed. Its electrochemistry and coordination properties shed light on potential mechanisms by which N₂-to-NH₃ reduction might be achieved.