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991.
The title compound was obtained in crystalline form suitable for X-ray structure determination. It forms crystals in the monoclinic space group P21/c with two centrosymmetric molecules in a unit cell of dimensions, a = 10.888(1) Å, b = 10.182(2) Å, c = 17.929(4) Å, β = 104.33(1)°. The central Mo2Cl2(O2C)2P2 core has effectively C2h-symmetry with the following principal dimensions: MoMo = 2.091(1) Å, MoCl = 2.405 Å, MoP = 2.566(2) Å, MoO(av.) = 2.103[4] Å, MoMoP = 104.38(7)°, and MoMoCl = 116.23(8)°. 相似文献
992.
Reed M. Izatt Don W. McBride James J. Christensen Jerald S. Bradshaw Glen A. Clark 《Journal of membrane science》1985,22(1):31-46
Carrier-mediated cation fluxes were determined using a H2OCHC13H2O liquid merebrane system for TlNO3 and for binary mixtures of either TlNO3 or KNO3 with alkali metal ions, alkaline earth metal ions, and Pb2+ (in the case of TlNO3). Both macrocyclic polyether and cryptand ligands were used as carriers. In Tl+Mn+ mixtures, selective transport of Tl+ was found over all cations studied, except in the cases of Ag+ by 2.2 and of Pb2+ by 18C6, DC18C6, ClDKP18C6, and 2.2. Generally, K+ was transported selectively from K+Mn+ mixtures, except in the cases of K+Tl+ mixtures in which Tl+ was transported selectively in all cases. A model relating cation flux to log K(CH3OH) for Mn+—macrocycle interaction and to ion-partitioning between the organic and aqueous phases was successful in rationalizing selective cation transport in most of the systems studied. 相似文献
993.
Reduction of [Ru2(CH3COO)2(C2O4)2(H2O)2]? by N-(2-hydroxyethyl)-ethylenediaminetriacetatoaquotitanium(III) [Ti(HEDTA)] involves several distinct stages. The first stage has a half-time of less than 1 ms, and is interpreted as a substitution reaction leading to a multinuclear intermediate. The second stage has a second-order rate constant of 5 x 103M?1s?1 [25°C, μ = 0.1 m (LiCF3SO3)]. The rate-limiting process for the second stage is electron transfer within the assembled multinuclear complex. Subsequent slower stages correspond to breakup of the multinuclear Ru(II)2-Ti(IV) complex formed by electron transfer. The overall rate of reduction of this oxidant by Ti(HEDTA) is less than the corresponding rate for the reaction in which Ti3+ acts as reductant, mainly because the stability of the binuclear complex is reduced by the presence of the aminoacid ligand. The data are consistent with the conclusion that the ligand increases the rate of intramolecular ET, probably by reducing geometric change associated with oxidation of Ti(III) to Ti(IV). 相似文献
994.
Application of the variable encounter method (VEM) has been made to the thermal cyclobutene decomposition system. Vibrational energy transfer in the cyclobutene-seasoned quartz surface system has been studied. The occurrence of strong collisions is demonstrated in crucial manner at temperatures below 400 K. 相似文献
995.
996.
Laser-induced fluorescence spectra for the first allowed electronic transition (22125 cm?1) of methylglyoxal (CH3COCHO) and its perdeutero analog (CD3COCDO) in a supersonic nozzle beam are quantitatively represented assuming that the potential function governing the CH3(CD3) rotation is changed during the transition. In the excited state the potential function is ternary (V1 = 95 (1 + cos 3θ)cm?1) as in the fundamental state (V0 = 134.5 (1 - cos 3θ)cm?1), but the minima are shifted by an angle of π/3. The spectrum of biacetyl (CH3COCH3CO) can be reproduced assuming two uncoupled methyl groups undergoing similar conformational changes during the electronic transition (the estimated potential function is V1 = 117.5 (1 + cos 3θ) cm?1 for each methyl group), in perfect agreement with the most recent assignment of the 0-0 transition. These results are consistent with ab initio calculations for the fundamental and first excited singlet states. 相似文献
997.
本文改进了分别由S.T.Yau,A.Ros及沈一兵给出的关于单位球面Sn+p的极小流形和复射影空间CP^n+p的Kaehler子流形及全实极小子流形的截面曲率的Pinching常数。 相似文献
998.
999.
O,O-Alkylenedithiophosphates of diorganotin(IV) of the type R2Sn[SP(S)O2G]2 (R = Me, Et, n-Bu, Ph; G = CH2CMe2CH2, CMe2CMe2, CMe2CH2CHMe) have been synthesized by the reactions of diorganotin(IV) dichlorides with ammonium O,O-alkylenedithiophosphates or that of diorganotin(IV) oxides with O,O-alkylenedithiophosphoric acids in 1:2 molar ratio in benzene. These new complexes are white solids which are soluble in common organic solvents and are monomeric in refluxing benzene; and they have been characterized by elemental analysis and by different spectroscopic (IR, 1H, 13C, 31P and 119Sn NMR) studies, on the basis of which a six coordinated octahedral structure has been suggested in solution. 相似文献
1000.