桥基原子对金属—金属作用的影响

本文借助EHMO法得到的Mulliken集居数和经验公式,讨论了过渡金属原子簇分子构型的稳定性和桥基与金属原子形成的平面距离D对其稳定性的影响。指出可用D值与实验上得到的距离d值的差别,判断过渡金属原子簇化合物金属—金属作用的强弱。     

MOLYBDENUM-IRON MIXED METAL CLUSTERS (Ⅰ)——THE SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF (η~5-C_5H_5)_2Mo_2Fe_2(μ_4-Te)(μ_3-Te)_2(CO)_6

The reaction of Fe_2(μ_3-Te)_2(CO)_9 with Mo_2(CO)_6(η~5-C_5H_5) affords the title compound. Its X-ray analysis shows a butterfly structure for the Mo_2Fe_2 core; the two molybdenum atoms occupy the hinge with a Mo—Mo bond distance of 2.819 and the two iron atoms are on the tops of the wings with an average Mo—Fe bond distance of 2.932(2). Each molybdenum is bonded to a Cp ring, and three CO ligands are terminally bonded to each iron atom. One tellurium atom quadruply bridges Mo_Fe_2 with Mo—Te(μ_4)=2.625(2). and Fe—Te(μ_4)=2.713(2). Two tellurium atoms triply bridge the two triangular Mo_2Fe faces with Mo—Te(μ_3)=2.678(1) and Fe—Te(μ_3)=2.513(3). The molecule has C_(2v) symmetry and a bicapped triangle bipyramidal skeleton. Crystallographic parameters are as follows: space groupImm2(orthorhombic), a=14.562(3), b=10.391(1), c=7.139(4), V=1080.2(i)~3, Z=2, ρ(cald)=1.819g·cm~(-3). The final R factor was 2.2％ for 620 independent reflections(I>2σ(I)).     

含氧桥的笼状化合物[Mo_5P_2O_(23)]~(6-)[(CH_3)_2NH_2]_5~(5+)-[H_3O]~+·1/2(CH_3)_2NCHo·1/2H_2O的合成和结构

[Mo_5P_2O_(23)]~(6-)[(CH_3)_2NH_2]_5~(5+)[H_3O]~+·1/2DMF·1/2H_2O(DMF=(CH_3)_2NC-HO)(M_r=1204.67)的晶体属三斜晶系,空间群P,晶胞参数a=16.438(6);b=22.22(1);c=11.325(5),α=104.25(4);β=108.97(3);γ=97.68(4)°,V=3688(3),Z=4,D_c=2.17gcm~(-1),R=0.056,R_w=0.074,晶胞中每个不对称单元含有两个[Mo_5P_2O_(23)]~(6-)[(CH_3)_2NH_2]_5~(5+)[H_3O]~+·1/2DMF·1/2H_2O,阴离子[Mo_5P_2O_(23)]~(6-)中的Mo、P原子成一个畸变五角双锥构型。有一个阴离子的所有原子(Mo、P、O)位置完全确定,而另一个阴离子有一个磷酸根的三个氧原子位置出现二重位置统计分布。化合物的阳离子为二甲胺阳离子和水合氢离子。     

二甲亚砜—二[4,4,4-三氟-1-(2-噻吩基)-1,3-丁二酮]合铜(Ⅱ)的晶体结构

β-二酮及其衍生物的配合物作为分离试剂、发光材料及化学位移试剂已日益引起人们的重视。近年来,人们还开辟了4,4,4-三氟-1-(2-噻吩基)-1,3-丁二酮(HTTA)的一些稀土配合物的结构和红外光谱的研究。为了对这类化合物的特殊功能及结构特点进行更广泛的研究,本文报道以二甲亚砜为轴向加合的HTTA过渡金属铜(Ⅱ)配合物的晶体结构。实验晶体的制备将Cu(OAc)_2·2H_2O和HTTA溶于乙醇中,混合后析出绿色沉淀。沉淀用体积比H_3O:C_2H_5OH=2∶1的混合溶剂重结晶,所得的微晶进行元素分析,结果与Cu(TTA)_2     

Synthesis and Crystal Structure of 1-D Chain Copper(Ⅱ) Complex:[Cu(L)Cl2]n(L = 2,5-Di-2-pyridyl-1,3,4-oxodiazole)

The title complex, [Cu(L)Cl2]n (L = 2,5-di-2-pyridyl-1,3,4-oxodiazole) 1, has mixture solvent of CH3CN and CH2Cl2 (L is generated from the metal-assisted hydrolysis reaction of bptz) and structurally characterized. It crystallizes in space group C2/c of monoclinic system with cell parameters: a = 9.812(2), b = 12.679(3), c = 1 1.111(2) A, β = 103.92(3)°, V = 1341.6(5)A3, Z = 4, Dc = 1.776 g/cm3, Mr= 358.66, F(000) = 716, μ = 2.024 mm-1 and S = 1.004. The final R = 0.0346 and wR = 0.0938 for 1011 observed reflections with I ＞ 2σ(I). The Cu( Ⅱ ) ion is six-coordinated by four N atoms of two L ligands and two Cl- ions in a distorted octahedral geometry. The ligand L acts as a bis-bidentate ligand to bridge the Cu( Ⅱ ) ions, resulting in an infinite chain structure.     

Synthesis and Structural Characterization of a New One-dimensional Infinite Chain of Silver(I) Complex with Triphenylphosphine

1 INTRODUCTION The tertiary phosphine silver(I) complexes for- mulated as [AgLnL] (L = tertiary phosphine; n = 1～4; L = coordinating or un-coordinating anions) were first prepared in 1937 by Mann, et al.[1]. Sil- ver(I), whose coordination number ranges…     

Syntheses and Crystal Structures of Two Novel 1-D Metal Complexes with Dicyanamide： [Zn（pheen）（dca）2]n and [Cu（quin）2（dca）2]n

1 INTRODUCTION Polymeric transition metal complexes with di-cyanamide have attracted considerable attention because of their interesting coordination and phy-sical properties in recent years[1]. The dicyanamide is a versatile ligand coordinated to metal…     

簇材料的研究进展和探索途径

元素周期表中金属元素和大多数非金属元素都能形成共价结合的同类原子多面体、环或链。它既可与别的元素生成化合物,也可单独存在,二者一般统称为原子簇化合物,本文以下简称为簇合物或簇。对于其中能以分立分子形式存在的称之为分子簇;具有     

二甲亚砜-二[4,4,4-三氟-1-(2-噻吩基)-1,3-丁二酮]合铜(II)的晶体结构

制备了标题化合物单晶,确定了它的分子和晶体结构,结果表明Cu(II)与五个氧原子配位,其中之一来自沿轴向(CH3)2SO.形成略为变形的四方锥结构.在配体上的噻吩基取顺式围绕差Cu(II)原子,这可以共轭效应来解释.