MoFe3S4单立方烷原子簇研究 IV:新型的双跨桥六配体单立方烷簇合物MoFe3S4(μ-Me2NCS2)2(Me2NCS2)4.2CH3CN的合成与结构

在二甲胺基二硫代甲酸钠、氯化亚铁及四硫代钼酸铵的自兜反应体系中, 以分步结晶法分离出MeFe3S4(Me2NCS2)5.CH2Cl2及MoFe3S1(Me2NCS2)6.2CH3CN等单立方烷簇合物, 并测定了后者的结构. 它的分子含两个Me2NCS2并具有最高核心氧化态[MoFe3S4]^6^+. 本文报道该化合物的结构特点, 指出在自兜反应体系中, 可能存在几种不同氧化态的单立方烷原子簇化合物.     

MoFe_3S_4单立方烷原子簇研究Ⅱ.MoFe_3S_4 (C_5H_(10)NCSS)_5的合成与结构

六氢吡啶基二硫代甲酸钠盐、氯化亚铁及四硫代钼酸铵在二甲基甲酰胺及二氯甲烷中,经一步自兜反应,分别得到了[MoFe_3S_4(C_5H_(10)NCSS)_5]DMF及[MoFe_3S_4(C_5H_(10)NCSS)_5]CH_2Cl_2。通过X射线衍射测定了后者的晶体结构,比较了它与[MoFe_3S_4(Et_2NCSS)_5]~-结构特点的异同,同时研究了反应物摩尔比对产物的影响以及溶剂分子的置换反应。     

铁铂硫原子簇化合物的合成与结构研究 V: [MoFe3S4]类立方烷簇合物的转化反应和[Et4N]3[Mo2Fe6S8(SC6H4CH3-m)3Cl6]的晶体结构

具[MoFe2S4]类立方烷结构单元的双类立方烷化合物[Et4N]4[Mo2Fe7S8(SR)12](1a,R=Ph; 1b, R=tolyl-m)或单类立方烷化合物[MoFe3S4(dteR2)5](2a, R=Me; 2b, R=Et)与酰氯在乙腈中反应, 分别得到不含Fe桥的双类立方烷化合物(Et4N)3[Mo2Fe6S8(SR)3Cl6](3a, R=Ph; 3b, R=toly-m)与[MoFe3S4]骨架支解后的Fe(dteR2)2Cl(4a, R=Me; 4b, R=Et)。说明在相同反应条件下, [MoFe3S4]单元在1中比在2中稳定, 本文首次将1型与3型结构通过一步化学反应连系起来。3型化合物的产生得到X射线衍射测定及^1H NMR谱的证实。本文报道3b的单晶结构及3的^!H NMR数据, 3b属六方晶系, P63/m, a=1.6827(3), c=1.5951(16)nm; V=3.91158nm^3; Dc=1.491g/cm^3;Z=2; F(000)=1780; 偏离因子R=0.048, 化合物2与酰氯反应产生4, 由红外及紫外可见光谱证实。     

铁铂硫原子簇化合物的合成与结构研究 V: [MoFe3S4]类立方烷簇合物的转化反应和[Et4N]3[Mo2Fe6S8(SC6H4CH3-m)3Cl6]的晶体结构

具[MoFe2S4]类立方烷结构单元的双类立方烷化合物[Et4N]4[Mo2Fe7S8(SR)12](1a,R=Ph; 1b, R=tolyl-m)或单类立方烷化合物[MoFe3S4(dteR2)5](2a, R=Me; 2b, R=Et)与酰氯在乙腈中反应, 分别得到不含Fe桥的双类立方烷化合物(Et4N)3[Mo2Fe6S8(SR)3Cl6](3a, R=Ph; 3b, R=toly-m)与[MoFe3S4]骨架支解后的Fe(dteR2)2Cl(4a, R=Me; 4b, R=Et)。说明在相同反应条件下, [MoFe3S4]单元在1中比在2中稳定, 本文首次将1型与3型结构通过一步化学反应连系起来。3型化合物的产生得到X射线衍射测定及^1H NMR谱的证实。本文报道3b的单晶结构及3的^!H NMR数据, 3b属六方晶系, P63/m, a=1.6827(3), c=1.5951(16)nm; V=3.91158nm^3; Dc=1.491g/cm^3;Z=2; F(000)=1780; 偏离因子R=0.048, 化合物2与酰氯反应产生4, 由红外及紫外可见光谱证实。     

一种新型的混合金属原子簇化合物(η^5-C5H5)4Mo4Fe2-(μ3-S)5(CO)5的合成和晶体结构

用(η^5-C5H5)2Mo2(CO)6和Fe3S2(CO)9在甲苯中的反应制备了一种新型混合金属原子簇化合物(η^5-C5H5)4Mo4Fe2-(μ3-S)5(CO)5.并用X-射线结构分析测定了它的晶体结构和分子结构.结果表明原子簇的骨架是由[FeMo3S4]的类立方烷孪合[MoFe2S]的三角锥,它们之间共用一个Fe原子.     

MoFe3单立方烷原子簇研究I.(Et~4N)[MoFe~3S~4(Et~2NCSS)~5]CH~3CN的自兜合成及结构

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。     

MoFe3S4单立方烷原子簇研究 III: 三核链状簇合物向单立方烷簇合物的转化及MoFe3S4(Et2NCS2)5.CH3CN的结构

以Fe(DMF)6[(FeCl2)2MoS4]与Et2NCS2Na在DMF中反应实现了三核链状簇骼向单立方烷簇骼的转化, 得到了MoFe3S4(Et2NCS2)5并测定了它的晶体结构. 本文指出与配体有关的氧化还原过程及配体的配位特点对这一转化反应及其产物的影响, 同时比较了由于核心氧化态的差异而造成的簇骼结构面貌的变化.     

链状三核钼(钨)硫原子簇化合物[M3O2S8]^2^-的合成, 光谱和晶体结构

本文以[NH4]2MOnS4-n(M=Mo, w, n=0-2)为原料, 在酸性和中性条件下, 合成出九个新的三核不对称钼硫和钨硫原子簇状化合物L2[M3O2S8][L=(n-Bu)4N, Ph4P,PyC16H33, (CH3)3NC16H33, Et4N], 用元素分析, 红外光谱, 紫外光谱对簇合物进行了表征, 并测定了其中[(n-Bu)4N]2[Mo3O2S8]和[n-Bu)4N]2[W3O2S8]两个簇合物的晶体结构。本文又一次验证了钼(钨)硫成簇反应是分子内部电子转反应, 并提出了反应历程。     

[(C2H5)4N]2{Fe4S4[S2CN(C2H5)2]4}的晶体和分子结构

[(C2H5)4N]2{Fe4S4[S2CN(C2H5)2]4}单晶样品在Nicolet-R3四圆衍射仪上收集X射线衍射数据. 分析结果给出其晶胞参数: a=22.125(6), b=11.313(3),c=25.053A; β=118.05(2)°; V=5534.19A^3, Z=4, 空间群Cc. 衍射数据经过Lρ因子和经验吸收效应校正. 分子中铁原子的位置从三维Patterson图上得到. 接着经过若干轮Fourier和差Fourier电子云密度合成, 发现全部其余非氢原子的坐标.氢原子位置根据理论模型计算. 结构修正最后收敛至R=0.073, Rw=0.069. 标题化合物是由[(C2H5)4N]^+和{FeS4[S2CN(C2H5)2]}^2^-组成的离子型化合物. 结构的主要特点表现在阴离子上, 而在阴离子中含有类立方烷型簇核Fe4S4. 该簇核中每个铁原子与五个硫原子配位, 其配位多面体构型均为畸变的四方锥.     

新奇的Mo/Fe/S原子簇的合成及[Me_3PhCH_2N]_2[MoFe_4S_4(SC_6H_(11))_7]的结构表征

在 (NH4) 2 MoS4,FeCl2 ,NaSC6 H1 1 (C6 H1 1 为环己基 )的甲醇反应体系中得到一种新型的 [Me3PhCH2 N] 2 [MoFe4S4(SC6 H1 1 ) 7]的钼铁硫立方烷原子簇 ,并进行了结构表征 .它的晶体属三斜晶系 ,空间群P 1,a =1.5 2 3 1( 3 )nm ,b =1.610 5 ( 3 )nm ,c=1.83 83 ( 4 )nm ,α =77.18( 3 )° ,β =75 .17( 3 )° ,γ =64 .60 ( 3 )° ,Z =2 .讨论了由于环烷巯基参与而引起的反应产物及其结构变化     

六核钴原子簇化学 3: 一些含Co~6八面体簇骼的原子簇化合物的合成、结构和电化学性质

(R~8P)~4-nCoX~n(R=Ph,Et 等;X=C,B=1,2)与Na~E~x(E=S,Se;X=1,2)在DMF或DMF/乙醇介质中反应得到了一系列六核钴的原子簇化合物Co~6(μ~3-E)~8(PR~3)~6.这些化合物含有正规的或畸变的Co~6八面簇骼.化合物可以用I~2氧化生成正一价的簇合物而不改变簇骼的几何构型,反达来,正一价的簇合物也可以被苊烯钠还生成中性的簇合物.本文还研究了这些化合物的电化学性质并提出了氧化还原反应的电子传递过程.     

Reduced mono-, di-, and tetracubane-type clusters containing the [MoFe3S4]2+ core stabilized by tertiary phosphine ligation

Treatment of oxidized clusters [(Cl4cat)(MeCN)MoFe3S4Cl3]2- (1) and [(Meida)MoFe3S4Cl3]2- (2) with tertiary phosphines in the presence of NaBPh4 in acetonitrile results in chloride substitution at the iron sites and the formation of clusters with the reduced [MoFe3S4]2+ core. Thus, 1 is a precursor to [(Cl4cat)(MeCN)MoFe3S4(PR3)3] (R = But (3), Pri (4)) and [(Cl4cat)2(Et3P)2Mo2Fe6S8(PEt3)4] (5). Cluster 2 affords [[(Meida)MoFe3S4(PCy3)3]4Fe2(mu-Cl)L2]3+ (L = THF (6), MeCN (7)). The structures of 3-7 were established by X-ray analysis. Clusters 3 and 4 are single cubanes, centrosymmetric 5 (previously reported in a different space group: Demadis, K. D.; Campana, C. F.; Coucouvanis, D. J. Am. Chem. Soc. 1995, 117, 7832) is a double cubane with a rhomboidal Fe2S2 bridge, and 6 and 7 are tetracubanes. In the latter, four Meida oxygen atoms from different cubanes bind each of two central high-spin Fe(II) atoms in trans-Fe(mu-Cl)LO4 coordination. The topology of these clusters is not precedented. Zero-field M?ssbauer parameters for all clusters are reported. Isomer shift considerations suggest the formulation [Mo3+Fe2+2Fe3+S4] for reduced clusters. Voltammetry of 3 and 4 reveals four-member electron transfer series encompassing the oxidation levels [MoFe3S4]4+,3+,2+,+ in the potential interval + 1.0 to -1.3 V vs SCE in dichloromethane. Compared to the clusters with monoanionic ligands at the iron sites, phosphine ligation shifts redox potentials to more positive values. This effect arises from reduction of cluster negative charge and the tendency of phosphines to stabilize lower oxidation states. The synthesis of reduced clusters 4 from 1 and of [Fe4S4(PPri3)4]+ from [Fe4S4Cl4]2- is accompanied by the formation of Pri3PS, detected by 31P NMR, indicating that the phosphine is the reductant. This result implies a similar function of tertiary phosphines in the synthesis of 3 and 5-7. (Cl4cat = tetrachlorocatecholate(2-); Meida = N-methyliminodiacetate(2-).)     

Synthesis and characterization of sulfur-voided cubanes. Structural analogues for the MoFe(3)S(3) subunit in the nitrogenase cofactor.

A new class of Mo/Fe/S clusters with the MoFe(3)S(3) core has been synthesized in attempts to model the FeMo-cofactor in nitrogenase. These clusters are obtained in reactions of the (Cl(4)-cat)(2)Mo(2)Fe(6)S(8)(PR(3))(6) [R = Et (I), (n)Pr (II)] clusters with CO. The new clusters include those preliminarily reported: (Cl(4)-cat)MoFe(3)S(3)(PEt(3))(2)(CO)(6) (III), (Cl(4)-cat)(O)MoFe(3)S(3)(PEt(3))(3)(CO)(5) (IV), (Cl(4)-cat)(Pyr)MoFe(3)S(3)(PEt(3))(2)(CO)(6) (VI), and (Cl(4)-cat)(Pyr)MoFe(3)S(3)(P(n)Pr(3))(3)(CO)(4) (VIII). In addition the new (Cl(4)-cat)(O)MoFe(3)S(3)(P(n)Pr(3))(3)(CO)(5) cluster (IVa), the (Cl(4)-cat)(O)MoFe(3)S(3)(PEt(3))(2)(CO)(6)cluster (V), the (Cl(4)-cat)(O)MoFe(3)S(3)(P(n)Pr(3))(2)(CO)(6) cluster (Va), the (Cl(4)-cat)(Pyr)MoFe(3)S(3)(P(n)Pr(3))(2)(CO)(6) cluster (VIa), and the (Cl(4)-cat)(P(n)Pr(3))MoFe(3)S(3)(P(n)Pr(3))(2)(CO)(6) cluster (VII) also are reported. Clusters III-VIII have been structurally and spectroscopically characterized. EPR, zero-field (57)Fe-M?ssbauer spectroscopic characterizations, and magnetic susceptibility measurements have been used for a tentative assignment of the electronic and oxidation states of the MoFe(3)S(3) sulfur-voided cuboidal clusters. A structural comparison of the clusters with the MoFe(3)S(3) subunit of the FeMo-cofactor has led to the suggestion that the storage of reducing equivalents into M-M bonds, and their use in the reduction of substrates, may occur with the FeMo-cofactor, which also appears to have M-M bonding. On the basis of this argument, a possible N(2)-binding and reduction mechanism on the FeMoco-cofactor is proposed.     

Synthesis and structure of the organometallic MFe2(mu3-S)2 clusters (M = Mo or Fe)

New organometallic clusters with the MFe2(mu3-S)2 core (M = Mo or Fe) have been synthesized from inorganic [MoFe3S4] or [Fe4S4] clusters under high pressure CO. The reaction of (Cl4-cat)2Mo2Fe6S8(PR3)6[R = Et, (n)Pr] with high pressure CO produced the crystalline [MoFe2S2]4+ clusters, (Cl4-cat)Mo(O)Fe2S2(CO)(n)(PR3)6-n[n= 4, Et =I, (n)Pr =II; n = 5, Et =III] after flash column chromatography. The similar [MoFe2S2]4+ cluster, (Cl4-cat)2MoFe2S2(CO)2(depe)(2)(IV), also has been achieved by the reactions of (Cl4-cat)MoFe3S3(CO)6(PEt3)2 with depe by reductive decoupling of the cluster. For the [Fe3(mu3-S)2]4+ cluster, [Fe4S4(PcHex3)4](BPh4) was reacted with high pressure CO to produce a new Fe3S2(CO)7(PcHex)(2)(V) compound. These reactions generalized the preparation of organometallic compounds from inorganic clusters. All the compounds have been characterized by single crystal X-ray crystallography. A possible reaction pathway for the synthesis of the MFe2(mu3-S) clusters (M = Mo or Fe) has also been suggested.     

Syntheses, structures, and reactivity of new pentamethylcyclopentadienyl-rhodium(III) and -iridium(III) 4-acyl-5-pyrazolonate complexes

New [CpM(Q)Cl] complexes (M = Rh or Ir, Cp = pentamethylcyclopentadienyl, HQ = 1-phenyl-3-methyl-4R(C=O)-pyrazol-5-one in general, in detail HQ(Me), R = CH(3); HQ(Et), R = CH(2)CH(3); HQ(Piv), R = CH(2)-C(CH(3))(3); HQ(Bn), R = CH(2)-(C(6)H(5)); HQ(S), R = CH-(C(6)H(5))(2)) have been synthesized from the reaction of [CpMCl(2)](2) with the sodium salt, NaQ, of the appropriate HQ proligand. Crystal structure determinations for a representative selection of these [CpM(Q)Cl] compounds show a pseudo-octahedral metal environment with the Q ligand bonded in the O,O'-chelating form. In each case, two enantiomers (S(M)) and (R(M)) arise, differing only in the metal chirality. The reaction of [CpRh(Q(Bn))Cl] with MgCH(3)Br produces only halide exchange with the formation of [CpRh(Q(Bn))Br]. The [CpRh(Q)Cl] complexes react with PPh(3) in dichloromethane yielding the adducts CpRh(Q)Cl/PPh(3) (1:1) which exist in solution in two different isomeric forms. The interaction of [CpRh(Q(Me))Cl] with AgNO(3) in MeCN allows generation of [CpRh(Q(Me))(MeCN)]NO(3).3H(2)O, whereas the reaction of [CpRh(Q(Me))Cl] with AgClO(4) in the same solvent yields both [CpRh(Q(Me))(H(2)O)]ClO(4) and [CpRh(Cl)(H(2)O)(2)]ClO(4); the H(2)O molecules derive from the not-rigorously anhydrous solvents or silver salts.     

钼簇合物反应性能的研究: {Mo3S4[S2P(OEt)2]4H2O}的加硫反应以及产物{Mo3(μ3-S)(μ-S2)3[S2P(OEt2]3I}的晶体结构

由贫硫化合物{Mo_3S_4[S_2P(OEt)_2]_4·H_2O}通过加硫获得了富硫化合物{Mo_3S_7[S_2P(OEt)_2]_3·I}(CH_8C_6H_5).化合物属三斜晶系,空间群PI,晶胞参数为a=10.350(1)A,b=13.931(4)A,c=16.369(3)A,α=103.69(2),β=86.62(1),γ=111.99(2)°,V=2183A~3;z=2,D_c=1.817g·cm~(-3).最终结构偏离因子R为0.042. 簇分子{Mo_3(μ_3-S)(μ-S_2)_3[S_2P(OEt)_2]3·I}属{Mo_3(μ3一Y)(μ-S_2)_3[S_2P(OEt)_2]_3·X}(Y=O,S;X=Cl,I)系列构型.{Mo_3}基本上是一个正三角形,Mo—Mo键长分别为2.721(1),2.724(1),2.725(1)A,Mo的配位多面体为七个硫原子组成的畸变五角双锥,有一个I原子联结着三个(S_2)~(2-)桥基的三个不与Mo共平面的S原子,I—S距离平均为3.169A,比相应的Van der Waals距离(～4.00A)明显地短,显示一定程度的成键作用,簇分子的这一构型是一种较为稳定的结构类型.