In this issue’s Review, T. Hofmann et al. discuss molecules and biological mechanisms that give rise to the tastes “sweet” and “umami”. How are taste receptors activated and signals transmitted to the cerebral cortex? The Highlights deal with the generation of hydrogen molecules and the first stars in the early universe (S. Schlemmer) and well-defined low-valent iron catalysts (O. García Manchenõ).
In the Communications section, T. Itoh et al. report on a cis-specific topochemical solid-state copolymerization of a charge transfer complex of 7,7,8,8-tetrakis(methoxycarbonyl)quinodimethane and 7,7,8,8-tetracyanoquinodimethane. V. Gevorgyan et al. describe a palladium-catalyzed carbocyclization of alkynyl ketones which proceeds via a carbopalladation pathway. S. Gambarotta et al. present a chromium ethylidene complex that catalyses ethylene trimerization (see picture).