Osmabenzenes can be easily synthesized from two η2‐coordinated olefin osmacycles in the presence of benzonitrile by means of facile hydrogen‐transfer conversions (see graphic). Mechanisms for the formation of osmabenzenes are proposed based on DFT calculations.
Block copolymers in seconds : Catalyst‐free, ambient‐temperature click conjugation of individual polymer strands becomes possible using novel ATRP‐derived cyclopentadienyl‐capped polymers in an extremely rapid hetero‐Diels–Alder cycloaddition with macromolecules equipped with electron‐deficient dithioester end groups prepared by the RAFT process.
Tungsten tryst : A 4‐H‐butatrienylidene complex of tungsten was successfully isolated and structurally characterized. It undergoes a unique self‐coupling, which leads to a dimer (see picture; P pink, O red) with a cross‐conjugated π system and with electrochemically and magnetically active metal centers.
Involuntary association : Anionic β‐galactosidase enzymes associate with positively charged Au nanoparticles to produce reduced‐charge conjugates, which assemble at oil–water interfaces to result in stable microcapsules (see picture). The microcapsules were formed quickly and showed high enzymatic activity, which makes them promising materials for biotechnology applications.
An energy‐transfer cascade is generated from a cationic conjugated polymer (PFP) and negatively charged, Y‐shaped DNA labeled with three dyes at its termini (fluorescein (Fl), Tex Red, and Cy5). Multistep fluorescence resonance energy transfer regulates the fluorescence intensities of PFP and the dyes. Different types of logic gates can be operated by observing the emission wavelengths of different dyes with multiplex nucleases as inputs.
Down to the wire : Photobleaching dynamics show the exciton delocalization length of directly linked porphyrin arrays (see picture) to be about four or five porphyrin units at the single‐molecule level. This result provides a better understanding of how light‐signal transmission occurs in the solid state and gives a perspective for the porphyrin arrays to be used as single‐molecule photonic wires.
RNA Lego : The use of natural riboswitch aptamers in synthetic RNA switches (see picture) should broaden the scope of artificial RNA regulators dramatically. It is shown that thiamine pyrophosphate (TPP) aptamers can be used in engineered devices as very sensitive switches of gene expression in unmodified organisms. The approach demonstrates that intrinsic metabolites can be utilized as external effectors of cellular functions.
On edge : Self‐assembled monolayers of a bis(hydrazone)‐based molecular grid physisorbed on graphite are studied by scanning tunneling microscopy (see picture). High order is attained at the supramolecular level by thermal annealing of the grid‐based films. A preferential edge‐on configuration of the molecular grid with respect to the substrate is found.
