Research articles

Self-assembly of discrete and well-defined supramolecular structures often requires a delicate balance of non-covalent forces such as hydrogen bonding and metal–ligand interactions. Now, by studying the formation of G-quadruplexes, it has been shown that the Coulombic energy associated with the separation of ion pairs can also be used to precisely regulate self-assembly processes.

The transport of bicarbonate anions across cell membranes by proteins is an important biological process, and if not regulated properly it can lead to cystic fibrosis and heart disease. Now, it has been shown that ‘small’ molecules can also promote efficient bicarbonate transport across lipid membranes and could be used to probe this process.

The presence of adenine–thymine base pairs in DNA duplexes significantly reduces their electrical conductivity. However, by replacing adenine with a closely related analogue that does not disturb the normal complementary base pairing, it is possible to make duplexes that can transfer charge efficiently without having to use only guanine–cytosine base pairs.

Porous materials with very different pore sizes and structures are commonly used for various applications. But although bicontinuous pore networks — with two interwoven yet unconnected channels — have been reported, tricontinuous structures have so far only been predicted theoretically. Now, researchers have prepared a mesoporous silica with three identical, interpenetrating channels.

Latent catalysts are usually activated by heating them or adding an external chemical agent, but now it has been shown that mechanical force is also an option in some instances. Ultrasound can be used to dissociate polymeric ligands from metal-containing complexes to reveal the innate catalytic ability of one of the two fragments.

Carbon–hydrogen bonds are strong and stable, rarely succumbing to the activation attempts of chemists. Certain bacteria are able to metabolize methane using a diiron-centred enzyme, but synthetic analogues have had much less reactivity. Now, an oxo-bridged diiron complex has been shown to have extremely high activity towards C–H bonds.

The enantioselective construction of quaternary stereocentres, particularly those with all-carbon substituents, is a challenging problem in asymmetric synthesis. It has now been shown that an alternative retrosynthesis of aldol products provides an opportunity to form such stereocentres with a reaction that creates three new carbon–carbon bonds in a single step.

A survey of protein–ligand complexes shows that hydrogen bonds and halogen bonds that share a common oxygen-atom acceptor are often geometrically perpendicular to one another. Moreover, theoretical studies on small-molecule models of such systems predict that these two interactions are energetically independent.

Water can behave in unexpected ways at high pressure and temperature. Simulations of the detonation of a high explosive show that ‘extreme’ water can act as a chemical catalyst that promotes the transport of oxygen between reactive sites — contrary to the current view of water as a stable final product.

Molecules confined to small volumes can contort themselves into unusual conformations that differ from those usually observed when no constraints are placed on them. It is now shown that when normal alkanes are encapsulated inside self-assembled capsules, they adopt a coiled conformation and exert pressure inside their hosts.

Two closely related species of fungus each produce one enantiomer of the same natural product. The biomimetic synthesis of both enantiomers reported here supports the unusual conclusion that the two species have evolved to produce a pair of enantiomerically distinct enzymes.

The spectrally resolved fluorescence of a zinc–porphyrin dimer is used to quantify intracellular viscosity. The porphyrin dimer also acts as a singlet-oxygen sensitizer, and enables real-time observation of a surprisingly large increase in intracellular viscosity that occurs on singlet-oxygen-mediated photoinduced cell death.

Performing chemical reactions on ultra-small scales is important in a number of disciplines. Now, it has been shown that a junction formed by fusing two polymer nanowires preloaded with reactants provides an effective attolitre-volume in which reactions can be conducted on a zeptomole (10⁻²¹ mol) scale.

Adding low concentrations of aromatic organic cations to an aqueous solution in which polyoxometalate-based crystals are immersed leads to the spontaneous growth of tubular structures with controllable diameters. Tubes can be fused together to form junctions and are shown to act as channels through which liquids can flow.

Short nucleotides with just one or two bases do not generally form stable hydrogen-bonded pairs in water. Now, however, it has been shown that the hydrophobic interior of water-soluble coordination cages offers a sheltered environment in which stable duplexes can be formed.