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41.
Noriko Shimizu Tomoji Ozeki Hideyasu Shikama Tsuneji Sano Masahiro Sadakane 《Journal of Cluster Science》2014,25(3):755-770
We found that three isomers of mono-Ru substituted Keggin-type germanotungstate with a dmso ligand, [GeW11O39RuII(dmso)]6?, could be formed by a reaction of α-Keggin-type mono-lacunary germanotungstate, [α-GeW11O39]8?, with Ru(dmso)4Cl2. The main isomer is an α-isomer, and the others are β2-isomer and β3-isomer, which were confirmed by 1H NMR, cyclic voltammetry, IR, and single crystal X-ray structure analysis. 相似文献
42.
Orto PJ Nichol GS Okumura N Evans DH Arratia-Pérez R Ramirez-Tagle R Wang R Zheng Z 《Dalton transactions (Cambridge, England : 2003)》2008,(32):4247-4253
The reactions of the previously reported cluster complexes [Re(6)(mu(3)-Se)(8)(PEt(3))(5)I]I, trans-[Re(6)(mu(3)-Se)(8)(PEt(3))(4)I(2)], and cis-[Re(6)(mu(3)-Se)(8)(PEt(3))(4)I(2)] with the [Re(6)(mu(3)-Se)(8)](2+) core with CO in the presence of AgSbF(6) afforded the corresponding cluster carbonyls [Re(6)(mu(3)-Se)(8)(PEt(3))(5)(CO)][SbF(6)](2) (), trans-[Re(6)(mu(3)-Se)(8)(PEt(3))(4)(CO)(2)][SbF(6)](2) (), and cis-[Re(6)(mu(3)-Se)(8)(PEt(3))(4)(CO)(2)][SbF(6)](2) (). Infrared spectroscopy indicated weakening of the bond in CO, suggesting the existence of backbonding between the cluster core and the CO ligand(s). Electrochemical studies focusing on the reversible, one-electron oxidation of the cluster core revealed a large increase in the oxidation potential upon going from the acetonitrile derivatives to their carbonyl analogs, consistent with the depleted electron density of the cluster core upon CO ligation. Disparities between the IR spectra and oxidation potential between and indicate that electronic differences exist between sites trans and cis to the location of a ligand of interest. The active role played by the Se atoms in influencing the cluster-to-CO bonding interactions is suggested through this result and density functional (DF) computational analysis. The computations indicate that molecular orbitals near the HOMO account for backbonding interactions with a high percentage of participation of Se orbitals. 相似文献
43.
Hydrogen generation from weak acids: electrochemical and computational studies of a diiron hydrogenase mimic 总被引:1,自引:0,他引:1
Felton GA Vannucci AK Chen J Lockett LT Okumura N Petro BJ Zakai UI Evans DH Glass RS Lichtenberger DL 《Journal of the American Chemical Society》2007,129(41):12521-12530
Extended investigation of electrocatalytic generation of dihydrogen using [(mu-1,2-benzenedithiolato)][Fe(CO)3]2 has revealed that weak acids, such as acetic acid, can be used. The catalytic reduction producing dihydrogen occurs at approximately -2 V for several carboxylic acids and phenols resulting in overpotentials of only -0.44 to -0.71 V depending on the weak acid used. This unusual catalytic reduction occurs at a potential at which the starting material, in the absence of a proton source, does not show a reduction peak. The mechanism for this process and structures for the intermediates have been discerned by electrochemical and computational analysis. These studies reveal that the catalyst is the monoanion of the starting material and an ECEC mechanism occurs. 相似文献
44.
45.
Yuki Nagao Nobuhiro Naito Fumitada Iguchi Noriko Sata Hiroo Yugami 《Solid State Ionics》2009,180(6-8):589-591
New proton-conductive polyamide oligomers, oligomeric poly[(1, 2-propanediamine)-alt-(oxalic acid)], were synthesized to investigate the proton transport properties of bulk and thin films. The obtained oligomers were characterized by the X-ray diffraction, FT-IR spectra, 1H NMR, Matrix Assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) mass spectrum, and electrical conductivity measurements. The bulk proton conductivity is 3.0 × 10? 4 S cm? 1 at the relative humidity (RH) of 80%. The proton conductivity of thin film is relatively higher than that of bulk sample. Thickness dependence of the proton conductivity was observed in these thin films. The maximum proton conductivity of the thin film is 4.0 × 10? 3 S cm? 1 at the relative humidity (RH) of 80%, which is higher one order magnitude than that of the bulk sample. The activation energies of bulk and 200 nm thick film are 1.0 and 0.69 eV at the RH of 60%, respectively. 相似文献
46.
47.
Direct, efficient syntheses of the benzimidazo[2,1-a]isoquinoline ring system have been achieved with 2-bromoarylaldehydes, terminal alkynes, and 1,2-phenylenediamines by a microwave-accelerated tandem process in which a Sonogashira coupling, 5-endo cyclization, oxidative aromatization, and 6-endo cyclization can be performed in a single synthetic operation. 相似文献
48.
Zheng-Ming Wang Noriko Yoshizawa Katsunori Kosuge Wendong Wang Geoffrey A. Ozin 《Adsorption》2014,20(2-3):267-274
Quiescent hydrothermal conditions were applied to synthesis of the sandwich nanocomposites of reduced graphite oxide (rGO) and periodic mesoporous silica (PMS) with vertically aligned mesochannels. It was found that the formation of the PMS–rGO–PMS sandwich structure is very sensitive to the surface and synthesis conditions. Although a higher temperature hydrothermal condition promotes reduction of GO and formation of bulky mesoporous nanoparticles, quiescent hydrothermal condition can serve as an alternative approach to obtain the unusual nanocomposites and slightly promote the structural stability of PMS on the surface of rGO. 相似文献
49.
Fu WW Shimizu N Takeda T Dou DQ Chen B Pei YH Chen YJ 《Chemical & pharmaceutical bulletin》2006,54(9):1285-1287
Three new A-ring lactone triterpenoid saponins, platycoside M-1 [3-O-beta-D-glucopyranosyl platycogenic acid A lactone], platycoside M-2 [3-O-beta-D-glucopyranosyl platycogenic acid A lactone 28-O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside], and platycoside M-3 [3-O-beta-D-glucopyranosyl platycogenic acid A lactone 28-O-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside], were isolated from the roots of Platycodon grandiflorum A. DC. Their chemical structures were elucidated on the basis of their spectral data and chemical evidence. 相似文献
50.
A significant acceleration effect of a beta-silicon atom was observed on the electrocyclic ring-opening reaction of benzocyclobutene derivatives to form o-quinodimethanes. This acceleration effect could be attributed to an electronic sigma-donating nature of the C(alpha)-Si(beta) bond, associated with alpha-anion driven pericyclic reactions. 相似文献