A new route to pyridine derivatives by the reaction of tris(isopropylthio)cyclopropenylium perchlorate with α-lithiated isocyanides

The reaction of tris(isopropylthio)cyclopropenylium perchlorate ( 1 ) with α-lithiated tosylmethyl, benzyl and benzoylmethyl isocyanides 2a-c in dry tetrahydrofuran gave the pyridine derivatives 3a-c respectively.     

Intramolecular rearrangement for regioselective complexation by intramolecular CH/pi interaction in a hydrophobic cavity of a ruthenium coordination sphere

A Ru(II) complex with a hydrophobic cavity formed from two 1-naphthoylamide groups was prepared. Its reactions with beta-diketones gave beta-diketonato complexes in which hydrophobic pi-pi or CH/pi interactions were confirmed by NMR spectroscopy and X-ray crystallography. In the case of the asymmetric beta-diketone benzoylacetone, an isomer with a CH/pi interaction was afforded as the sole product owing to thermodynamic control. The reaction was found to involve a novel intramolecular rearrangement from the phenyl-included isomer to the methyl-included one without rupture of Ru-beta-diketonato coordination bonds (activation energy 52 kJ mol(-1)). This indicates that CH/pi interactions can be more favored thermodynamically than pi-pi interactions in a suitable hydrophobic environment.     

Photoresponsive rolling and bending of thin crystals of chiral diarylethenes

Dithienylhexafluorocyclopentene with (R)- or (S)-N-phenylethylamide substituents formed rod-like and 0.2-1.0 microm-thick platelike crystals by sublimation; upon UV irradiation, the crystals bent concavely to the incident light and finally rolled crystals were obtained; the bent crystals were reconverted to flat crystals by visible light irradiation.     

Functional Near‐Infrared Fluorescent Probes

Near‐infrared (NIR) fluorescent probes have attracted much attention, but despite the availability of various NIR fluorophores, only a few functional NIR probes, that is, probes whose absorption and/or fluorescence spectra change upon specific reaction with biomolecules, have been developed. However, functional probes operating in the NIR range that can be targeted to protons, metal ions, nitric oxide, β‐galactosidase, and cellular stress markers are expected to be effective for fluorescence imaging in vivo. This Focus Review concentrates on these functional NIR probes themselves, not their applications.     

Preparation of poly(ethylene glycol)-modified poly(amido amine) dendrimers encapsulating gold nanoparticles and their heat-generating ability

Loading of HAuCl4 in poly(amido amine) G4 dendrimers having poly(ethylene glycol) (PEG) grafts at all chain ends and subsequent reduction with NaBH4 yielded PEG-modified dendrimers encapsulating gold nanoparticles (Au NPs) of ca. 2 nm diameter. The Au NPs held in the dendrimers were stable in aqueous solutions and dissolved readily, even after freeze-drying. Despite their small particle size, the heat-generating ability of Au NPs held in the dendrimer was comparable to that of widely used Au NPs with ca. 11 nm diameter under visible light irradiation. The observed excellent colloidal stability, high heat-generating ability and their biocompatible surface confirm that the PEG-modified dendrimers encapsulating Au NPs are a promising tool for photothermal therapy and imaging.