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131.
From a reaction system including benzoic acid and Mn(NO3)2 in alkali medium, two hexanuclear manganese benzoate cluster compounds have been synthesized. A compound [Et4N]2[Mn6(PhCOO)14] has been structurally characterized, which contains hexanuclear Mn11 moieties extending unlimitedly to form one-dimensional linear structure. Carboxyl oxygen atoms are bridged in variety of modes to the Mn atoms, forming an arrangement like a sinusoid for the Mn atoms. The structural parameters of these compounds were compared with the data obtained from EXAFS determination for the Mn cluster in the OEC of PS11, supporting that the coordination sphere of the Mn site in the OEC may contain carboxyl bridges. The possible combination modes between the carboxyl group and the Mn atoms have been suggested. The NMR signals exhibit widening and shift produced by the influence of the paramagnetic Mn" sites. The red-shift of the absorption in IR spectrum was observed to be attributed to the coordination of the carboxyl group to the Mn 相似文献
132.
关于ABS树脂热失重数据的计算 总被引:1,自引:0,他引:1
在解析TG曲线时,常用的方法有积分法和微分法,但反应级数需要通过预先假定和尝试确定.本文以ABS树脂热解反应为对象,采用三次样条插值函数求得热解反应速率,利用二元线性回归经一次计算,同时求得ABS树脂热解反应表观活化能E,视频因子A以及反应级数n,并把所得结果与积分法和微分法作了比较,确定了各自方法所适用的转化率区间.本文还考察了不同升温速率对热解动力学参数的影响. 相似文献
133.
134.
三重桥氧三核铬甲酸配合物在乙炔、水汽系统中的反应行为及其热解过程的研究 总被引:1,自引:0,他引:1
研究[Cr_3(M_3-O)(M-OOCH)_6(H_2O)_2OOCH)·xH_2O[表示为(Cr_3FF)],在乙炔、水汽系统中的反应行为时发现,当温度高于220℃时,脱了部分配体的(Cr_3FF)碎片具有活化乙炔进行加氢和加水反应的性能。为进一步探讨这些活性组分,综合采用了差热分析(DTA),热重分析(TGA),高温X射线粉末衍射(HXRD)和红外光谱法(IR)对(Cr_3FF)的热解过程进行定性、定量研究。基于此,讨论了活性组分的本质。 相似文献
135.
136.
Peng Jing-Hai Kang Bei-Sheng Hong Mao-Chun Weng Ling-HongFuzhou Laboratory of Structural Chemistry Fujian Institute of Research on the Structure ofMatter Chinese Academy of Sciences Fuzhou Fujian 《结构化学》1993,(5)
<正> Co3(S2C6H4)3{P(C4H9)3}3 ·2CH2Cl2, Mr = 1373. 45, mono-clinic, space group P21/c, a = 16. 110(5), b=36.313(10), c=13. 502(5) A , β= 105. 69(4)% V=7604. 4 A3, Z = 4, Dc = 1. 20 g. cm-3, μ=10. 03 cm-1, and F (000) = 2990. R(Rw) is 0. 086(0. 091) for 4559 observed unique reflections. The three cobalt atoms in the complex form an isosceles triangle with an average Co -Co bond distance of 2. 504(5) A. The average values of Co - S and Co - P bond distances are 2. 271(7) A , and 2. 198(8) A , respectively. 相似文献
137.
Synthesis and Crystal Structure of a Decanuclear Silver(Ⅰ)-thiolate Compound Ag_(10)S[S_2P(OEt)_2]_8
Introduction Polynuclear Ag(I)-thiolate compounds are of interests due to their unique molecular structures and metal-metal interactions. There were some such compounds reported in literatures, including Ag8(6-S)(dtp)6 [dtp=S2P(OEt)2] with [Ag8] cube,1 {Ag[S2P(OC3H7)2]}6 with a [Ag6] distorted octahedron,2 Ag11S(Et2dtc)9 [Et2dtc=S2CN(C2H5)2] with a [Ag11] cage of a 3-fold axis,3 and Ag14(6-S)(SPh)12(PPh3)8 4CH3OH13H2O with a [Ag14S12] cage composed of a staggered [Ag6] octahedr… 相似文献
138.
ZHONG Shi-Jun WANG Yin-Gui ZHANG Qian-ErState Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Science Fuzhou Fujian China.Department of Chemistry and Institute of Physical Chemistry Xiamen University Xiamen Fujian China 《中国化学》1994,(4)
The molecular orbitals obtained from conventional quantum chemistry calculations, are expressed in terms of symmetrized valence bond functions of fragment, and a direct picture of chemical bonding can be drawn easily. This method is utilized, together with extended Huckel calculations, to interpret the bonding properties of a centipede-like chain structure for novel laser-producing boranes B3k+pH5k+p+3- which is constructed from the repeated unit B3H5 linked to each other by three B-H-B bonds. 相似文献
139.
<正> Title compound Na5Y (WO4)4 (Mr = 1195. 24) crystallizes in the space group I41/a with the cell parameters a= 11. 447(7), c= 11. 336(1) A , Z = 4, V = 1485(2) A3, A = 5. 34 g/cm3. A(MoKα) = 0. 71069 A. F(000) = 2702, final R = 0. 045,Rw = 0. 054 for 936 observed reflections with I≥3σ(I). The title compound has a scheelite structure.In this paper, we also give the X-ray powder diffraction data of Na5Y(WO4)4 obtained by using a D/max-ra type diffractometer. 相似文献
140.
利用原位红外光谱研究标题化合物在N2 中的反应行为。发现它们在不同温度下能使乙酸分别转化为丙酮和甲烷。它们对乙酸的丙酮化反应活性顺序 :[V3OAT]>[VFe2 OAT],[V2 CrOAT]>[Fe3OAT],[VCr2 OAT]>[Cr3OAT][OAT =(μ3 O) (μ O2 CCH3) 6(THF) 3]。它们对乙酸的甲烷化反应活性顺序 :[Cr3OAT]>[VCr2 OAT],[V2 CrOAT]>[V3OAT]>[VFe2 OAT],[FeO3OAT]。对乙酸的丙酮化反应活性[Fe3OAT]明显低于 [Fe3OAH][OAH =(μ3 O) (μ O2 CCH3) 6(H2 O) 3]。对乙酸的甲烷化反应活性 [Cr3OAT]也明显低于 [CrOAH]。并对上述 [Fe3OAT],[Cr3OAT]与 [Fe3OAH],[Cr3OAH]之间差异进行了讨论。 相似文献