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171.
用X_α方法对CH_4在Ni(Ⅲ)表面吸附解离反应的理论研究马晨生,马理,杨忠志(吉林大学理论化学研究所,长春,130023)关键词CH_4/Ni(Ⅲ)吸附体系,原子簇模型,CH_4/Mi_7,MS-X_α-SCF方法甲烷在Ni表面的催化重整反应在工业和国... 相似文献
172.
The nucleophile [ArTe−] generated in situ borohydride solution of Ar2Te2, reacts with 2-(chloromethyl) tetrahydrofuran and 2-(2-bromoethyl)-1,3-dioxolane resulting in L1 and L2, respectively. The complexes of palladium(II) and platinum(II) with L1/L2 having stoichiometries [MCl2·L2], [ML2](ClO4)2, [(DPPE)ML2](ClO)4)2, [(PPh3)2ML2](ClO4)2 and [(phen)ML2](ClO4)2 (where L = L1/L2 DPPE = Ph2PC H2CH2PPh2, PHEN = 1,10-phenanthroline and M = Pd/Pt) have been synthesized. IR, 1H, 125Te{1H} and 31P{1H} NMR and UV-vis spectral data of these species in conjunction with their molar conductance and molecular weight data have been used to authenticate the new species. In all complexes (1–20) the ligands L1 and L2 are coordinated through tellurium and in the complexes of formula [ML2](ClO4)2 (M = Pd, Pt) the ligand is bidentate with the oxygen atom used in complexation. In solution, complexes PtCl2L2 exist as a mixture of cis and trans isomers whereas only the trans isomer was observed for the palladium analogues. The [(phen)PdL2](ClO4)2(Q) quenches 1O2 readily. The plot of log [Q] vs time is linear. Mechanism compatible with the experimental observations is proposed. 相似文献
173.
钒(Ⅴ)—Ferron—NaBrO3体系极谱吸附催化波的研究 总被引:5,自引:0,他引:5
在pH5.8乙酸盐缓冲溶液中,V(Ⅴ)-7-碘-8-羟基喹啉-5-磺酸-NaBrO3体系产生一灵敏的吸附平行催化波,二次导数峰高与V(Ⅴ)浓度在2.9×10-9~4.7×10-7mol/L范围内呈线性关系,检出限为1×10-9mol/L.研究了电极反应机理,方法应用于水中钒的测定,结果满意. 相似文献
174.
Aacute;gnes Buvári-Barcza Antal Csámpai Lajos Barcza 《Journal of inclusion phenomena and macrocyclic chemistry》2002,42(3-4):209-212
Two guests reacting with cyclodextrins (CDs) may form ternary complexes, in addition to the common competition of 1:1 complexes. One of the guests can really be included into the cavity of the CD, while the second guest molecule is either inserted close to the first one or attached to the outer surface of the supramolecule by H-bonding. There is a further possibility when the included guest bears a substituent outside the cavity and the second guest can interact with it. The properties of the ternary species formed are highly influenced by the solely (or primarily) included guest. The changes are attributed to the altered properties of the hydrophilic domain of the CD. The phenomena can be proved by NMR data obtained for some binary systems of -CD inclusion complexes and acetic acid and by the stability constants of the ternary complexes formed. Allosteric effects as well as coenzyme/apoenzyme/substrate interactions could be well modelled by these types of CD complexes. 相似文献
175.
The activity coefficients at infinite dilution have been measured at 25°C for cyclohexane, cyclohexene, 1,3-cyclohexadiene, 1,4-cyclohexadiene, benzene, n-hexane, 1-hexene, 1-hexyne, n-heptane, 1-heptene and 1-heptyne in decahydronaphthalene, bicyclohexyl, 1,2,3,4-tetrahydronaphthalene and cyclohexylbenzene. These results, together with previously determined H
m
E
and V
m
E
have been used to calculate the partial molar excess thermodynamic properties of mixing at infinite dilution. 相似文献
176.
177.
MENG Jian REN Yu-Fang LI Xiao-GuangLaboratory of Rare Earth Chemistry Physics Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun Jilin ChinaPopov V.V. Repin S.M. Smirnov LA. loffe Physicotechnical Institute Russian Academy of Sciences Saint Petersburg Russia 《中国化学》1994,12(5):419-424
YBa2Cu3-xVxO7-y(x=0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6) superconductors have been prepared. X-ray diffraction shows that the system remains orthorhombic for all compositions studied, but for x > 0.4 V2O5 was detected as an impurity phase. Substitution of V5+ for Cu2+ occurs in the Cu(2) sites on the Cu(2)-O planes. The introduction of the high valence element, vanadium, produces the extra free-electrons. These electrons recombine with the positive carrier of the system. It makes depression of the mobility and the Hall number of YBa2Cu3-xVxO7-v and also results in a depression of TC. 相似文献
178.
179.
The intramolecular electrophilic substitution in 6-functionalized 1,3-dimethyl-1H-pyrrolo[3,4-d]pyrimidine-2,4(3H,6H)-diones was used for the synthesis of pyrimido[4′,5′:3,4]-pyrrolo[1,2-a]quinoxaline-8,10(7H,9H)-dione, pyrimido[4′,5′:3,4]pyrrolo[2,1-c][1,2,4]benzo-triazine-8,10(7H,9H)-dione, and 2H-pyrimido[4′,5′:3,4]pyrrolo[1,2-a]indole-2,4,11(1H, 3H)-trione derivatives.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2180–2185, December, 2006. 相似文献
180.
The title compound, cobalt 4′,7-diethoxylisoflavone-3′-sulfonate([Co(H2O)6](X)2⋅8H2O, X = C19H17O4SO3) was synthesized and its structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in the triclinic space group P-1 with cell parameters a = 9.026(3) Å, b = 16.431(5) Å, c = 18.195(6) Å, α = 72.289(4)∘, β = 87.498(4)∘, γ = 82.775(5)∘, V = 2550.1(13) Å−3, Dc = 1.419 Mg m−3, and Z = 2. The results show that the title compound consists of one cobalt cation, six coordinated water molecules, eight lattice water molecules, and two 4′,7-diethoxylisoflavone-3′-sulfonate anions, C19H17O4SO−3. Two anions have different conformations. Twelve H atoms of six coordinated water molecules, as donors, form hydrogen bonds with four oxygen atoms of sulfo-groups of two anions and eight oxygen atoms of eight lattice water molecules. In addition, π < eqid1 > ⋅ < eqid2 > π stacking interactions exist in the crystal structure, which together with hydrogen bonds lead to supramolecular formation with a three-dimensional network. 相似文献