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Linear Mo-Fe-S cluster complexes with basic unit of MoS_4 can be divided into four types ac-cording to the central Mo-S skeleton (S_2MoS_2Fe, S_2MoS_2FeS_2MoS_2, S_2MoS_2FeS_2Fe, FeS_2MoS_2Fe).Ten such complexes with various ligands and cations were synthesized, and their crystal structureswere determined and characterized by electron spin resonance, infrared and electron absorptions,Mossbauer and magnetic effects. Atomic distances from crystallographic analysis were comparedsystematically with respective spectroscopic data. There is strong evidence indicating that electrontransfers from Fe(Ⅱ) to Mo(Ⅵ), in spite of the fact that the apparent oxidation state of molyb-denum in most of the aforementioned complexes remains six. The probability of this electrontransfer depends strongly on the environment of Fe(Ⅱ). The fact that MoS_4~(2-) is both a goodbidentate ligand and an effective electron transfer unit is also evidence for its presence in manymolybdoenzymes and as a catalytically active center. 相似文献
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一个新型的V_2Ag_2S_4异金属立方烷簇合物从包含(NH_4)_3VS_4,Ag(PPh_3)_2NO_3,OC_4H_8dtcNa以及PhSNa的自兜反应体系中分离。标题化合物的晶体属单斜晶系,空间群C2/c,a=20.448(3),b=15.086(2),c=17.923(2),β=109.32°。用1500个I>3σ(I)的衍射数据进行精修,R=0.068。化合物中金属表观价态为Ⅴ(Ⅳ)与Cu(Ⅰ)。结构特点表明存在着从Ag(Ⅰ)到Ⅴ(Ⅳ)的部分电子转移。另讨论了反应体系中各物料的作用和可能的形成机理。 相似文献
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4-氨基-3,5-二甲基-1,2,4-三唑与水杨醛缩合形成4-(邻羟苯基亚甲基)-亚胺-03,5-二甲基-1,2,4-三唑Schiff碱(SATZ),该Schiff碱与Cu(ClO4)2.6H2O形成配合物Cu(satz)2.6H2O,分子式为C22H22CuN8O2.6H2O。 相似文献
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芳氢与配位硫原子之间(sp2C-H…S)的分子内氢键 总被引:1,自引:0,他引:1
化合物(Et4N)2[Pd2(mp)2(Hmp)2](1)(H2mp=2-巯基苯酚)的1H NMR谱中芳氢H16的峰出现在δ 8.79处,与预测值(δ 7.1)相差1.7,这是由于H16与配位硫S2原子之间存在弱相互作用,即新型的sρ2C-H…S之间的氢键作用.原子间距离C16…S2(0.361pm)和H16…S2(0.295pm)分别小于相应原子的范德华半径之和(0.370pm和0.305pm),C16-H16…S2角为128.1°,证明了这种新型氢键的存在.此外,在分子振动光谱中观察到这种氢键的作用使得芳氢υC-H出现在低于3000cm-1处.通过与类似物[Pd2(PPh3)2(Hmp)2Cl2](2)的比较,以及1在DMSO溶剂中仍然保持O-H…O和C-H…S这2种氢键的事实,表明C-H…S之间的作用,对1的配体Hmp中的苯环与Pd2S2平面之间的夹角偏离90°可能是有贡献的. 相似文献
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Itiswellknownthatinnaturetheactivationandreductionofdinitrogeninairtoammoniaarecatalyzedbynitrogenaseatambienttemperatureandpressure.ThemaincomponentsoftheactiveclusterofMoFeproteininnitrogenaseareMcluster(MoFe7S9cluster)andPcluster(Fe8S8cluster)[1].Inthel… 相似文献
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The mononuclear manganese complex Mn(phen)(CF3COO)(H2O)3(NO3 (C14H14O8N3F3Mn) has been synthesized, where phen = 1,10-phenanthroline. The molecular and crystal structures were determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group P21/c with a = 8.8550(3), b = 10.6529(3), c = 19.8763(2) A, β = 97.762(2)o, V = 1857.78(8) A3, Z = 4, Mr = 464.22, Dc = 1.660 g/cm3, μ = 0.789 mm-1, F(000) = 940, T = 293(2) K, R = 0.0764 and wR = 0.2441 for 1995 observed reflections with I > 2σ(I). In the crystal the manganese atom is six-coordinated by two chelated nitrogen atoms from phenanthroline, three oxygen atoms from water molecules and one oxygen atom from trifluoroacetate, completing an octahedral geometry. 相似文献
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双齿含硫配位体,二乙胺基二硫代甲酸钠盐与氯化亚铁及四硫代钼酸铵在二甲基甲酰胺溶液中,经一步自兜反应得到(Et~4N)[MoFe~3S~4(Et~2NCSS)~5]CH~3CN(1).X射线单晶结构测定表明1具有类立方烷骨架,核心价态为[MoFe~3S~4]^4^+,通过对1的阴离子结构分析,指出配位基的双齿螯合作用对化合物的稳定性及结构的影响。化学键理论计算也解释了阴离子中的主要键长特点。 相似文献
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自从计算机在化学领域中应用以来,化学结构的正规编码已广泛用来作为一种化学文献的信息索引,它还在开发化学智能系统中发挥着重要作用。正规编码生成是以化学结构图的拓扑性质为基础的。本文首先概述编码的基本原理及其生成的方法,随后分析这种编码在当今文献数据库、化学反应数据库、分子设计以及合成反应路线规划等化学信息系统中的功能。 相似文献
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