Chemistry of polynuclear metal complexes with bridging carbene or carbyne ligands. Part 63. Synthesis of eight-membered-ring metallacycles: X-ray crystal structures of [Pt4W4(-CR)(3-CR)3(-CO)(CO)7(?-C5H5)4]CH2Cl2, [Ni2Pt2W4(-CR)(3-CR)3(-CO)(CO)7(?-C5H5)4]CH2Cl2(R = C6H4Me-4), and [Ni2Pt2W4(3-CPh)4(C
Chemistry of polynuclear metal complexes with bridging carbene or carbyne ligands. Part 63. Synthesis of eight-membered-ring metallacycles: X-ray crystal structures of [Pt4W4(-CR)(3-CR)3(-CO)(CO)7(?-C5H5)4]CH2Cl2, [Ni2Pt2W4(-CR)(3-CR)3(-CO)(CO)7(?-C5H5)4]CH2Cl2(R = C6H4Me-4), and [Ni2Pt2W4(3-CPh)4(C
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具有桥联卡宾或卡炔配体的多核金属配合物的化学。
DOI：
10.1039/dt9870002189
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发表时间：
1987
期刊：
影响因子：
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通讯作者：
F. Stone
中科院分区：
文献类型：
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作者：
G. P. Elliott;J. Howard;T. Mise;C. M. Nunn;F. Stone
[Pt3W4（µ-CC6H4Me-4）2（µ 3-CC6H4Me-4）2（CO）8（η-C5H5）4]与[Pt（cod）2]（cod =环辛-1，5-二烯）在四氢呋喃（thf）中反应得到化合物[Pt4W4（µ-CC6H4Me-4）（µ 3-CC6H4Me-4）3（µ-CO）（CO）7（η-C5H5）4]。后者也可以由四核金属簇合物[Pt2W2（µ-CC6H4Me-4）（µ 3-CC6H4Me-4）（CO）4（cod）（η-C5H5）2]与乙烯在压力下反应得到。[Pt_4W_4（μ-CC_6H_4Me-4）（μ_3-CC_6H_4Me-4）_3（μ-CO）（CO）_7（η-C_5H_5）_4]的结构经X射线衍射确定。该分子有一个由八个金属原子组成的环，其中四个铂原子和四个钨原子处于交替位置，这样钨原子形成了“星”的四个点，铂原子基本上呈正方形排列（平均Pt = Pt 2.954，平均Pt-W 2.754 A）。三个tolylmethylidyne组三重桥Pt2W三角形，而第四边桥Pt-W键。其中两个µ 3-CC6H4Me-4基团位于Pt4W4环的一侧，而第三个位于另一侧。在这一侧，CO配体也不对称地桥接Pt2W三角形，在对称异构体中，Pt2W三角形将被µ 3-CC6H4Me-4片段占据。一个CO基团桥接Pt-W键，该Pt-W键邻近由边缘桥接的甲苯次甲基配体所跨越的Pt-W键。剩余的六个羰基半桥接其他六个Pt-W键。三金属化合物[PtW2（µ-CC6H4Me-4）2（CO）4（η-C5H5）2]与过量[Ni（cod）2]反应得到化合物[Ni2Pt2W4（µ-CC6H4Me-4）（µ 3-CC6H4Me-4）3（µ-CO）（CO）7（η-C5H5）4]。后者通过铂和镍位点的交换形成为两种异构体的混合物。在一种异构体中，甲苯基次甲基配体边缘桥接Ni-W键，而在另一种异构体中桥接Pt-W键。X射线衍射研究表明，在晶体中存在两种异构体，导致镍和铂位点的无序。在Ni_2Pt_2W_4环中，存在trans-Ni Ni和trans-Pt Pt排列，正如从合成模式所预期的。用过量的[Ni（cod）2]处理[PtW2（µ-CPh）2（CO）4（η-C5H5）2]，得到八核Ni2Pt2W4金属络合物，其形成为三种异构体的可分离混合物：[Ni2Pt2W4（µ-CPh）（µ 3-CPh）3（µ-CO）（CO）7（η-C5H5）4]（两种异构体）和[Ni2Pt2W4（µ 3-CPh）4（CO）8（η-C5H5）4]。对后者的X射线衍射研究证实了八元金属环的存在，其中四个钨原子位于"星星"的点上，并且有一个中心Ni Pt Ni Pt片段。四个CPh配体三重桥接NiPtW三角形，两个位于通过八个金属原子的平均平面上方，两个位于该平面下方。该结构具有通过环中心的晶体学双重轴。通过在七原子链状配合物[Pt3W4（µ-CC6H4Me-4）2（µ 3-CC6H4Me-4）2（CO）8（η-C5H5）4]上加成[Ni（cod）2]，合成了一个簇合物[NiPt3W4（µ-CC6H4Me-4）（µ 3-CC6H4Me-4）3（µ-CO）（CO）7（η-C5H5）4]（两个异构体）.在THF中，在回流温度下，物质[Pt4W4（µ-CC6H4Me-4）（µ 3-CC6H4Me-4）3（µ-CO）（CO）7（η-C5H5）4]和[Ni2Pt2W4（µ-CR）（µ 3-CR）3（µ-CO）（CO）7（η-C5H5）4]（R = Ph或C6H4Me-4）容易异构化为具有四个三重桥连次烷基的各自的对称形式。13 C-{1H}和195 Pt-{1H} n.m.r.报告了各种化合物的数据，并结合分子结构进行了讨论。
The reaction between [Pt3W4(µ-CC6H4Me-4)2(µ3-CC6H4Me-4)2(CO)8(η-C5H5)4] and [Pt(cod)2](cod = cyclo-octa-1,5-diene) in tetrahydrofuran (thf) affords the compound [Pt4W4(µ-CC6H4Me-4)(µ3-CC6H4Me-4)3(µ-CO)(CO)7(η-C5H5)4]. The latter may also be obtained from the reaction between the tetranuclear metal cluster [Pt2W2(µ-CC6H4Me-4)(µ3-CC6H4Me-4)(CO)4(cod)(η-C5H5)2] and ethylene under pressure. The structure of [Pt4W4(µ-CC6H4Me-4)(µ3-CC6H4Me-4)3(µ-CO)(CO)7(η-C5H5)4] has been established by X-ray diffraction. The molecule has a ring of eight metal atoms with the four platinum and four tungsten atoms in alternating positions, such that the tungsten atoms form the four points of a ‘star’, and the platinum atoms lie in an essentially square arrangement (mean Pt ⋯ Pt 2.954, mean Pt–W 2.754 A). Three of the tolylmethylidyne groups triply bridge Pt2W triangles, while the fourth edge-bridges a Pt–W bond. Two of the µ3-CC6H4Me-4 groups lie on one side of the Pt4W4 ring, while the third is on the other side. On this side also a CO ligand asymmetrically bridges the Pt2W triangle which in a symmetrical isomer would have been occupied by a µ3-CC6H4Me-4 fragment. One CO group bridges the Pt–W bond adjacent to that spanned by the edge-bridging tolylmethylidyne ligand. The remaining six carbonyl groups semi-bridge the other six Pt–W bonds. The reaction between the trimetal compound [PtW2(µ-CC6H4Me-4)2(CO)4(η-C5H5)2] and an excess of [Ni(cod)2] affords the compound [Ni2Pt2W4(µ-CC6H4Me-4)(µ3-CC6H4Me-4)3(µ-CO)(CO)7(η-C5H5)4]. The latter is formed as a mixture of two isomers by interchange of the platinum and nickel sites. In one isomer a tolylmethylidyne ligand edge-bridges a Ni–W bond, and in the other a Pt–W bond. An X-ray diffraction study showed that in the crystal both isomers are present, leading to disorder at the nickel and platinum sites. In the Ni2Pt2W4 rings there is a trans-Ni ⋯ Ni and a trans-Pt ⋯ Pt arrangement, as expected from the mode of synthesis. Treatment of [PtW2(µ-CPh)2(CO)4(η-C5H5)2] with an excess of [Ni(cod)2] yields an octanuclear Ni2Pt2W4 metal complex formed as a separable mixture of three isomers: [Ni2Pt2W4(µ-CPh)(µ3-CPh)3(µ-CO)(CO)7(η-C5H5)4](two isomers) and [Ni2Pt2W4(µ3-CPh)4(CO)8(η-C5H5)4]. An X-ray diffraction study on the latter species confirmed the presence of the eight-membered metal ring in which four tungsten atoms are at the points of a ‘star’ and there is a central Ni ⋯ Pt ⋯ Ni ⋯ Pt fragment. Four CPh ligands triply bridge the NiPtW triangles, two lying above the mean plane through the eight metal atoms, and two below this plane. The structure has a crystallographic two-fold axis through the centre of the ring. A cluster compound [NiPt3W4(µ-CC6H4Me-4)(µ3-CC6H4Me-4)3(µ-CO)(CO)7(η-C5H5)4](two isomers) has been prepared by addition of [Ni(cod)2] to the seven-metal-atom chain complex [Pt3W4(µ-CC6H4Me-4)2(µ3-CC6H4Me-4)2(CO)8(η-C5H5)4]. In thf at reflux temperatures, the species [Pt4W4(µ-CC6H4Me-4)(µ3-CC6H4Me-4)3(µ-CO)(CO)7(η-C5H5)4] and [Ni2Pt2W4(µ-CR)(µ3-CR)3(µ-CO)(CO)7(η-C5H5)4](R = Ph or C6H4Me-4) readily isomerise to their respective symmetrical forms with four triply bridging alkylidyne groups. The 13C-{1H} and 195Pt-{1H} n.m.r. data for the various compounds are reported, and are discussed in relation to the molecular structures.