Volume 1 Issue 9, December 2009

New web-based models of scholarly communication have made a significant impact in some scientific disciplines, but chemistry is not one of them. What has prevented the widespread adoption of these developments by chemists — and what are the prospects for adoption over time?

Can philosophy make worthwhile contributions to science? Eric Scerri thinks it can, and looks at what it has brought to the table for chemistry.

In spite of the many functions of copper proteins within biology, those that contain a single copper ion can be divided into two classes, based in part on their spectroscopic properties. An artificial 'type 0' protein combines some properties of both, and may offer a route to stable catalytic processes.

The formation of a phosphine oxide with its strong P=O bond is the driving force for the classical Wittig reaction, but is wasteful and can pose problems during purification. A new development allowing the use of catalytic phosphorus reagents promises to clean up olefination chemistry.

The conformational structure of a molecule can have important effects on its interactions and properties, but studying such effects is made difficult by the challenge of separating different conformers. Their spatial separation has now been achieved using an electric field — allowing the possibility of isomer-specific studies.

Proton-conducting solids are crucial components in a variety of electrochemical and energy-conversion devices. A porous metal–organic framework loaded with guest molecules displays both proton-conducting and gas-tight properties, affirming its potential as a fuel cell membrane.

Chemists are like detectives: they like to know 'whodunit' during a catalytic reaction. Combining advanced electron microscopy with intelligent molecular design has now provided strong evidence for the presence of a highly active site within a complex catalytic solid.

Shining circularly polarized light into a suspension of racemic amino-acid-derivative crystals in a saturated solution and then grinding them results in enantiomerically pure crystals. This evolution is shown to be directed by an unknown chiral product.

Encapsulating guest molecules inside host structures ranging from soft, flexible enzymes to rigid, porous zeolites has led to developments in many areas, including catalysis, sensing and separation. This Review highlights how metal–organic frameworks — materials formed by linking metal centres with organic ligands — can combine softness with regularity to produce dynamic, yet crystalline, structures that may prove useful for a range of applications.

Materials built from metal centres and organic ligands have traditionally attracted attention for their channels’ host–guest properties. Now, controlling the occupancy of the channels by guest molecules has resulted in a framework that conducts protons under anhydrous conditions and acts as a gas-tight membrane, offering a promising approach to fuel-cell electrolytes.

Copper-containing proteins can be classified into types 1 and 2, depending on their functional or spectroscopic properties. Now, a protein that fits neither type has been built using a scaffold made from the protein Pseudomonas aeruginosa azurin.

A cooperative reaction is reported whereby the halogenation of one silicon atom on a surface is shown to induce, invariably, halogenation of a neighbouring silicon. This is a first step towards using surface-propagated cooperative reactions to create molecular-scale patterns on surfaces.

Small alkanes are typically isomerized on tungstated-alumina solid-acid catalysts, but the origin of the activity has been unclear. Now, high-resolution imaging has revealed subnanometre Zr-WO_x clusters to be the active sites.

Complete chiral symmetry breaking of an amino acid derivative is achieved by circularly polarized light irradiation of a solution of the racemate in contact with racemic crystals, followed by abrasive grinding. The chirality of the amino acid derivative in the resultant crystals is fully determined by the rotation sense of the irradiation.

An organic polymer scaffold has now been developed that can capture and release functionalized inorganic nanoparticles by the threading and de-threading of pseudorotaxane linkages. The capture–release cycles are reversible and programmable both chemically and electrochemically. In mixtures of different nanoparticles, the scaffold can capture one type selectively — thus acting as a selective nanoparticle ‘sponge’.

Magnesium is commonly found in rocks and sea water as well as living organisms. Paul Knochel relates how this element has also sparked a great deal of interest among chemists.