ChemPhysChem

The organization of mono- and multilayer structures of nanoparticles is an important aspect of nanoscale chemistry. These nanoparticles are connected to a substrate by a variety of linking groups and forces. The nanoparticle architectures have facilitated the development of a wide range of new devices. The picture shows an oligocation-crosslinked array of anionic gold nanoparticles.

Hexameric building blocks are found in a range of materials, such as hydrocarbons and water. Using water as a model compound, this Highlight identifies some of the important new results, from both the theoretical and experimental viewpoints, in the characterization of stable hexameric structures. The picture shows the most stable hexamer in the gas phase, the water “cage”.

Just how different are the energies of left- and right-handed alanine enantiomers because of parity violation? Substantial advances in electroweak quantum chemistry have provided new answers to this question. The present, advanced calculations lead to the conclusion that numerous previous claims of L-alanine stabilization by parity violation are unjustified. This introduces some extra pepper into current discussions of the origin of biomolecular homochirality. The picture shows a zwitterionic model with conformational changes and solvent effects, as included in the calculations.

The question is reopened, whether L- or D-alanine is more stable. Calculated parity-violating energy shifts for the 13 stable conformers of gaseous alanine (the picture shows the global minima) indicate that the stabilization of a certain enantiomer is strongly dependent on its conformation. Naturally occurring L-alanine is preferred for only seven of the investigated structures, which allows no definite conclusion on the relative stability of the two chiral forms to explain the origin of homochirality in living organisms.