Intramolecular double‐hydrogen tunneling in porphycene (see picture) is investigated. Low‐temperature conditions are ensured by doping of single molecules into superfluid helium nanodroplets. The investigation of fluorescence excitation and dispersed emission spectra and the highly dissipative environment allows the observation of mode‐selective tunneling splitting and reveals a purely concerted tunneling mechanism for all isotopic variants of porphycene.
Very long range surface‐enhanced Raman scattering is observed from a nickel nanowire that is separated by 120 nm from a pair of gold nanodisks. The excitation of the surface‐plasmon resonance (SPR) from the gold nanodisk pair generates an enhanced electromagnetic field near the nickel segment (SEM, left), leading to Raman intensity greater than the nickel alone (right).
Diaminations are a girl's best friend : New reactions in the field of transition‐metal‐catalyzed diamination of olefins provide a powerful tool for the elaboration of more complex molecules bearing the 1,2‐diamine moiety. An overview of these methods, including asymmetric versions, is given.
A cholesterol‐based membrane tether…? system has been developed, for the attachment of lipid bilayer membranes at silica and gold surfaces, by S. D. Evans et al. in their Full Paper on page 6363 ff. Arrays of membrane have been produced by using deep UV lithography on both metallic and insulating substrates. Their response to electric fields demonstrates the formation of highly resistive, fluid membranes.
Finding a clear route to new structures : The design of an adaptable time warping (ATW) methodology (see figure) for automatically, quickly, and reliably deciphering X‐ray diffraction patterns is described.
On an atomic scale and with high sensitivity, solid‐state NMR spectroscopy can provide information about the electronic spin density and coupling mechanisms in paramagnetic compounds. The picture shows how the hyperfine splitting collapses through relaxation. Insights into which compounds are suitable and which approximations have to be made are given.
Gold'n'beads : A chemiluminescence immunoassay for the sensitive and rapid determination of AFP has been developed, employing bromophenol blue as a novel chemiluminescence enhancer by taking advantages of easy separation by magnetic beads and signal amplification by gold nanoparticles based on a sandwich‐type immunoreaction (see scheme).
ReacTiO 2 ns for rings : Gold nanoparticles supported on TiO2 are used as a novel heterogeneous catalyst for the isomerization of epoxides to allylic alcohols by a concerted mechanism (see scheme). The reaction proceeds in high yields and the product selectivity is often remarkable.
PS, I love you! Novel mixed phosphole/thiophene π‐conjugated systems were synthesized and their electronic properties have been studied both experimentally by UV/Vis spectroscopy and electrochemistry and by theoretical calculations. Exploiting the chemistry of both P‐ and S‐heteroles allows the generation of a diverse range of novel ring‐fused benzophosphole–thiophene derivatives.
Keeping their cool : Fabrication of a 2D weblike nanonetwork of gold was successfully demonstrated through a two‐step procedure including complexation of gold precursors to a weblike supramolecular assembly of surfactant followed by in situ reduction of the precursors to gold. Molecular assemblies stabilized by hydrogen bonding provided a sound template, leading to the highly integrated structure of gold through room‐temperature (cold) nanostructure fusion.
Adding an aryne to a tertiary allylamine affords o‐allylaniline products of an aza‐Claisen rearrangement. The aryne simultaneously provides the π component for the rearrangement and the quaternization event that lowers the activation energy for the sigmatropic shift. The reaction was applied to the synthesis of medium‐ring benzannulated amines (see scheme).
Available in small print : Block copolymer lithography has great potential for reducing the size and fabrication time of integrated circuits. Hydrogen‐bonding‐mediated molecular recognition in self‐assembly processes can be used to produce highly ordered square arrays of block copolymers on the surface of a silicon substrate (see picture).
Get selective! A selective oxidation of 1,2‐diols to α‐hydroxyketones catalyzed by organotin compounds has been developed (see scheme). Invaluable chemo‐ and stereoselectivity were found in the reaction. The catalytic system has been achieved by electrochemical and chemical oxidation.
Radical assembly : Halogen bonding has been observed for the first time between an isoindoline nitroxide and an iodoperfluorocarbon (see figure), which cocrystallize to form a discrete 2:1 supramolecular compound in which N? O.???I halogen bonding is the dominant intermolecular interaction. This illustrates the potential use of halogen bonding and isoindoline nitroxide tectons for the assembly of organic spin systems.
