Volume 3 Issue 4, April 2011

A model based on the well-known β-cyclodextrin–adamantane receptor–ligand pair has been used to obtain important insight into the kinetics of gradient-driven motion across a surface.

Photosynthesis in plants converts energy from the Sun into chemical fuel in the form of glucose. Now, a strategy to combine carbon dioxide reduction and photochemical water splitting, using a recyclable hydrogen donor, offers the opportunity to develop non-biomimetic photosynthesis.

Controlled energy-transfer on a molecular scale is a goal in many areas of science, from artificial photosynthesis to molecular electronics. Now, DNA origami has been used to direct the transfer of energy from an excited input dye down one of two paths by precisely arranging a mediator dye.

Photocatalysts such as titanium dioxide that use sunlight to split water and produce hydrogen would be a clean and sustainable solution to many problems, but their efficiency is currently too low to be widely used. Two approaches to engineer the surface properties of titanium dioxide offer hope that its efficiency can be increased.

Recently, individual organic molecules have been imaged with atomic resolution using non-contact atomic force microscopy with functionalized tips and scanning tunnelling hydrogen microscopy. The resulting applications of these techniques and further improvements of ultra-high spatially resolved molecular investigations are discussed in this Perspective.

Efforts to make graphene more useful for applications include altering its bandgap and increasing its processability. Both of these can be solved by chemically modifying the material, and now a wet chemical method has been developed that functionalizes graphene in bulk starting from pristine graphite.

Methanol is an abundant, renewable chemical feedstock. Here, a homogenous iridium catalyst enables a byproduct-free C–C coupling of methanol and allenes, producing higher alcohols that incorporate all-carbon quaternary centres. This process represents the first catalytic C–C coupling of methanol to provide discrete products of hydrohydroxymethylation.

It is shown that long-lived reactive oxygen intermediates are formed in heterogeneous reactions of ozone with aerosol particles, resolving apparent discrepancies between earlier quantum mechanical calculations and kinetic experiments. These intermediates play a key role in the chemical transformations and adverse health effects of toxic and allergenic air particulates.

The ability of TiO₂ photocatalysts to absorb solar light has so far been limited to the UV because of their large bandgap. Now, a surface phase of TiO₂ that possess a narrower bandgap closely matching the visible light energy has been synthesized at the surface of pure rutile TiO₂(011) faces.

Photochemical reduction of CO₂ usually requires the use of a sacrificial electron donor (reductant). Here, a tertiary amine reductant is described that can be regenerated by H₂ addition. This permits the formal coupling of CO₂ reduction to photochemical water splitting, thereby offering an approach to artificial photosynthesis.

Small modifications to the organic linkers in metal–organic framework materials (MOFs) can profoundly change their properties. Now, selective in situ esterification of a carboxylic-acid-based linker leads to a MOF with two types of channel having different surface chemistries. Adsorption into these channels is independent and can be switched using thermal or chemical triggers.

Some memory materials rely on a phase change between crystalline and amorphous phases that is triggered by a laser or electrical pulse. Although it is commonly believed that the materials go through a liquid phase, it is now shown that this may not always be the case.

The kinetics of multivalent interactions at interfaces is poorly understood despite its fundamental importance for (bio)molecular motion and molecular recognition events at biological interfaces. Here, directional spreading of multivalent molecules has been observed, and multiple surface diffusion mechanisms have been identified and dubbed walking, hopping and flying.

Intermolecular non-polar H···H interactions between polyhedrane molecules may be as attractive as classical hydrogen bonds. A theoretical study identifies the chemical and structural factors that favour such attractive interactions.

Marine bacteria and algae engage in intermittent symbioses mediated by unknown molecular signals. Here, it is shown that a chemical signal, p-coumaric acid, produced by the breakdown of algal lignin, causes the usually symbiotic bacterium Phaeobacter gallaeciensis to produce new metabolites (the roseobacticides) with potent but selective algaecidal activity.

Pilar Goya, Nazario Martín and Pascual Román relate how element 74 can be found in lamp filaments or weapon parts and also in literature, and continues to serve many purposes — no matter which of its two names it is given.