Influence of water on molecular forms of rhodamine B in dip-coated thin films

Dip-coated thin films including rhodamine B have been prepared using the sol-gel reaction of tetraethyl orthosilicate under relative humidity of 30% and 60%. They have been aged under relative humidity of 20%, 60%, and 95% for 5 days. According to the absorption spectra, just after the preparation of the films and under higher humidity, a larger amount of the dimers (H-and J-types) were formed in the films. Five days after the preparation of the films and aged under higher humidity, the H-dimer increased. On the other hand, the J-dimer increased, regardless of humidity under which the films were aged.     

Charge‐Transfer Phase Transition of a Cyanide‐Bridged FeII/FeIII Coordination Polymer

Heterometallic Prussian blue analogues are known to exhibit thermally induced charge transfer, resulting in switching of optical and magnetic properties. However, charge‐transfer phase transitions have not been reported for the simplest FeFe cyanide‐bridged systems. A mixed‐valence Fe^II/Fe^III cyanide‐bridged coordination polymer, {[Fe(Tp)(CN)₃]₂Fe(bpe)?5 H₂O}_n, which demonstrates a thermally induced charge‐transfer phase transition, is described. As a result of the charge transfer during this phase transition, the high‐spin state of the whole system does not change to a low‐spin state. This result is in contrast to FeCo cyanide‐bridged systems that exhibit charge‐transfer‐induced spin transitions.     

Preparation of the TiO2 Thin Film Photocatalyst by the Dip-Coating Process

Titanium dioxide (TiO2) coated glass-plate thin film photocatalysts for elimination of air pollutants, were prepared by the dip-coating process with titanium alkoxide including polyethylene glycol (PEG). The surface structure of these thin films changed drastically with the size of the PEG. They were either transparent or opaque. Nitrogen oxides (NOx), one of the most hazardous of air pollutants, were found to be efficiently eliminated by the thin film photocatalyst. The photocatalytic activities of the transparent and opaque thin films were found to be almost equal. This may be due to the two films having the same surface area. The highest activity was obtained for thin films around 1 m.     

Nickel-catalyzed cross-coupling of unactivated alkyl halides and tosylate carrying a functional group with alkyl and phenyl Grignard reagents

By the use of catalytic amounts of a nickel salt and a 1,3-butadiene, primary and secondary alkyl Grignard reagents undergo cross-coupling with alkyl bromides, iodide, and tosylate carrying a functional group such as amide, ester, and ketone at 0 °C in THF. The present procedure provides a simple, convenient, and practical method for construction of carbon chains in the presence of various functional groups. PhMgBr also gave the corresponding coupling product in a moderate yield.     

ComplexK-theory ofBSL3(Z)

ComplexK-theory ofBSL₃(Z) andBSt₃(Z) are computed. We first study a Brown-Peterson (BP) version of Soulé's arguments. Then we consider complexK-theory by using a Conner-Floyd type theorem.     

Synthesis and Stereochemical Revision of the C31–C67 Fragment of Amphidinol 3

Amphidinol 3 (AM3) is a marine natural product produced by the dinoflagellate Amphidinium klebsii. Although the absolute configuration of AM3 was determined in 1999 by extensive NMR analysis and degradation of the natural product, it was a daunting task because of the presence of numerous stereogenic centers on the acyclic carbon chain and the limited availability from natural sources. Thereafter, revisions of the absolute configurations at C2 and C51 were reported in 2008 and 2013, respectively. Reported herein is the revised absolute configuration of AM3: 32S, 33R, 34S, 35S, 36S, and 38S based on the chemical synthesis of partial structures corresponding to the C31–C67 fragment of AM3 in combination with degradation of the natural product. The revised structure is unique in that both antipodal tetrahydropyran counterparts exist on a single carbon chain. The structural revision of AM3 may affect proposed structures of congeners related to the amphidinols.     

Stereoselective synthesis of methyl (Z)-(4,4-difluoro-2,3,4,5-tetrahydro-1H-1-benzazepin-5-ylidene)acetate using a dianion Horner-Wadsworth-Emmons reagent

Stereoselective synthesis of methyl (Z)-(4,4-difluoro-2,3,4,5-tetrahydro-1H-1-benzazepin-5-ylidene)acetate (1a) is described. Z-selectivity of the Horner-Wadsworth-Emmons (HWE) reaction was obtained based on an investigation of the reaction conditions for introduction of a methylidene group onto the 5-position of benzazepine.