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61.
Yoshida K Furuyama T Wang C Muranaka A Hashizume D Yasuike S Uchiyama M 《The Journal of organic chemistry》2012,77(1):729-732
We report synthesis of dibenzoaluminepin as the first aluminepin, an aluminum analogue of borepin and gallepin. This compound contains one molecule of ethereal solvent on the Al atom, which adopts a tetrahedral geometry. The central 7-membered aluminepin ring has a boatlike conformation and was characterized by single-crystal X-ray diffraction, (1)H/(13)C NMR, and DFT studies. In addition, NICS, NBO, and theoretical calculations provide insight into the nature of the bonding and aromaticity of aluminepins. 相似文献
62.
Asano Y Sato J Furuyama T Kobayashi N 《Chemical communications (Cambridge, England)》2012,48(36):4365-4367
A gable-type zinc phthalocyanine and a derived planar bis-phthalocyanine containing a shared anthracene unit have been synthesized and their spectroscopic properties examined. The former showed a split Q band, while the latter exhibited a red-shifted but unsplit Q band, as explained by exciton coupling theory and molecular orbital calculations. 相似文献
63.
Oda Masayuki Xi Zhaoyong Inaba Satomi Slack Ryan L. Ishima Rieko 《Journal of Thermal Analysis and Calorimetry》2019,135(5):2647-2653
Journal of Thermal Analysis and Calorimetry - Metal–protein interactions are not necessarily tight in many transient biological processes, such as cellular signaling, enzyme regulation, and... 相似文献
64.
Yoko Shiraishi-Yamaguchi Yumi Sato Rieko Sakai Akihiro Mizutani Thomas Kn?pfel Nozomu Mori Katsuhiko Mikoshiba Teiichi Furuichi 《BMC neuroscience》2009,10(1):25
Background
Homer is a postsynaptic scaffold protein that links various synaptic signaling proteins, including the type I metabotropic glutamate receptor subunits 1α and 5, the inositol 1,4,5-trisphosphate receptor, Shank and Cdc42 small GTPase. Overexpression of Homer induces changes in dendritic spine morphology in cultured hippocampal neurons. However, the molecular basis underpinning Homer-mediated spine morphogenesis remains unclear. In this study, we aimed to elucidate the structural and functional properties of the interaction between Cupidin/Homer2 and two actin-cytoskeletal regulators, Cdc42 small GTPase and Drebrin. 相似文献65.
We investigated the dynamics of spontaneous emission from a photonic crystal etched into a SiN slab. After fitting the decay curves of the emission to double exponential functions, we divided the dynamic process of the spontaneous emission into a fast process and a slow process. It was observed that the presence of the photonic crystal increased the proportion of the fast decay component, and consequently, the emission rate and time-integrated emission intensity were also enhanced. These enhancements were a result of the coupling of the guide modes to the leaky modes of the photonic crystal slab waveguide. 相似文献
66.
Junji Saito Mitsuhiko Onda Shigekazu Matsui Makoto Mitani Rieko Furuyama Hidetsugu Tanaka Terunori Fujita 《Macromolecular rapid communications》2002,23(18):1118-1123
The catalytic behavior of three bis(phenoxy‐imine) group‐4 transition‐metal complexes (M = Ti, Zr, Hf), with iBu3Al/Ph3CB(C6F5)4 cocatalyst systems towards propylene polymerization was investigated under atmospheric pressure at 25 °C. The Ti complex produced ultrahigh‐molecular‐weight atactic poly(propylene), whereas Zr and Hf complexes formed high‐molecular‐weight isotactic poly(propylene)s via a site‐control mechanism. The isotactic poly(propylene) obtained with the Hf complex displayed a high melting temperature of 123.8 °C.
67.
Yusaku Ogura Masahiro Nakano Hajime Maeda Masahito Segi Taniyuki Furuyama 《Molecules (Basel, Switzerland)》2022,27(9)
Herein, we report the synthesis of sulfur-substituted boron(III) subphthalocyanines (SubPcs) with cationic axial ligands. Subphthalocyanines were synthesized by a condensation reaction using the corresponding phthalonitriles and boron trichloride as a template. An aminoalkyl group was introduced on the central boron atom; this process was followed by N-methylation to introduce a cationic axial ligand. The peripheral sulfur groups shifted the Q band of SubPcs to a longer wavelength. The cationic axial ligands increased the polarity and enhanced the hydrophilicity of SubPcs. The effect of axial ligands on absorption and fluorescence properties is generally small. However, a further red shift was observed by introducing cationic axial ligands into the sulfur-substituted SubPcs. This change is similar to that in sulfur-substituted silicon(IV) phthalocyanines. The unique effect of the cationic axial ligand was extensively investigated by theoretical calculations and electrochemistry. In particular, the precise oxidation potential was determined using ionization potential measurements. Thus, the results of the present study provide a novel strategy for developing functional dyes and pigments based on SubPcs. 相似文献
68.
Kazutoyo Endo Rieko Hirunuma Taeko Shinonaga Mitsuru Ebihara Hiromichi Nakahara 《Hyperfine Interactions》1994,91(1):557-561
The chemical states of iron in sixteen Antarctic meteorites belonging to H-group chondrites were studied by means of Mössbauer spectroscopy. An Fe-Ni alloy, troilite, paramagnetic Fe(III), and two kinds of paramagnetic Fe(II) were observed in each meteorite. The Mössbauer parameters indicated that the Fe(II) components can be assigned to olivine and some pyroxenes. The relative area intensities of Fe(III) in the chondrites correlated positively with iodine content, which was determined by radiochemical neutron activation analysis, and those of two Fe(II)-species correlated negatively with the content. On the basis of the data on the halogen and the Mössbauer spectrocopy, the terrestrial contamination on Antarctic meteorites is discussed. 相似文献
69.
The kinetics of the gas-phase dehydrogenation of cyclopentane to cyclopentene is found to be consistent with a slow attack by an I atom (step 4, text) on cyclopentane in the range 282–382°C. The measured rate constants fit the Arrhenius equation, log k4 = 11.95 ± 0.08 – (24.9 ± 0.23)/θ 1 mole?1 sec?1, where θ = 2.303 R T in kcal/mole. This leads to a value of ΔH = 24.3 ± 1 kcal/mole and a bond dissociation energy DH = 94.9 ± 1 kcal/mole. The latter value is identical with DH0(i-Pr-H) = 95 ± 1 kcal/mole and signifies that cyclopentane and the cyclopentyl radical have the same strain energy. Arrhenius parameters are deduced for all six steps in the reaction mechanism. Surface reactions are shown to be unimportant. Cyclopentyl iodide is an unstable intermediate in the reaction and the rate constant for its bimolecular formation from HI + cyclopentene is found to be log k6 = 8.40 ± 0.29 - (26.9 ± 0.8)/θ 1 mole?1 sec?1. Together with the equilibrium constant, this yields for the unimolecular elimination of HI from cyclopentyl iodide, the rate constant, log k5 = 13.3 ± 0.3 – (42.8 ± 1.2)/θ sec?1. 相似文献
70.
Rieko Furuyama 《Journal of organometallic chemistry》2005,690(20):4398-4413
Based on new results as well as the reported data, the ethylene and propylene polymerization behavior of bis(phenoxy-imine) Ti complexes (Ti-FI Catalysts) combined with MAO (particularly that of their fluorinated versions) is discussed, with an emphasis on the characteristics and mechanisms of living ethylene and syndioselective living propylene polymerization. Unlike common living olefin polymerization catalysts, fluorinated Ti-FI Catalysts with MAO display thermally robust living behavior and polymerize ethylene in a highly controlled manner at temperatures as high as 50 °C. Additionally, despite being C2-symmetric catalysts, fluorinated Ti-FI Catalysts/MAO mediate highly syndioselective living propylene polymerization. Fluorinated Ti-FI Catalysts that we developed are the first examples of catalysts that induce the living polymerization of both ethylene and propylene. In addition, they are also the first examples of living and, at the same time, highly stereoselective propylene polymerization catalysts. The versatile and robust living nature of the fluorinated Ti-FI Catalysts allows the preparation of a wide variety of unique living polymers; some of which can even be produced catalytically. On the basis of theoretical calculations as well as experimental results, we conclude that these unusual polymerization features of fluorinated Ti-FI Catalysts originate from an attractive interaction between the ligand and a growing polymer chain and/or the fluxional character of the catalyst coupled with 2,1-regiochemistry. This is in stark contrast to group 4 metallocene catalysts, which control olefin polymerization mainly by repulsive interactions based on the rigidly organized ligand frameworks. 相似文献