Synthesis and properties of the divalent 1,2-bis(dimethylphosphino)ethane (dmpe) complexes MCl2(dmpe)2 and MMe2(dmpe)2 (M=Ti, V, Cr, Mn, or Fe). X-ray crystal structures of MCl2(dmpe)2 (M=Ti, V, or Cr), MnBr2(dmpe)2, TiMe1.3Cl0.7(dmpe)2, and CrMe2(dmpe)2
Synthesis and properties of the divalent 1,2-bis(dimethylphosphino)ethane (dmpe) complexes MCl2(dmpe)2 and MMe2(dmpe)2 (M=Ti, V, Cr, Mn, or Fe). X-ray crystal structures of MCl2(dmpe)2 (M=Ti, V, or Cr), MnBr2(dmpe)2, TiMe1.3Cl0.7(dmpe)2, and CrMe2(dmpe)2
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二价 1,2-双（二甲基膦基）乙烷 (dmpe) 配合物 MCl2(dmpe)2 和 MMe2(dmpe)2（M=Ti、V、Cr、Mn 或 Fe）的合成和性质。
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发表时间：
1985
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通讯作者：
M. Hursthouse
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作者：
G. Girolami;G. Wilkinson;A. Galas;M. Thornton;M. Hursthouse
过渡金属二氯化物与 1,2-双(二甲基膦基)乙烷 (dmpe) 反应生成颜色鲜艳、高度结晶的八面体配合物 trans-MCl2(dmpe)2（M = Ti、V、Cr 或 Fe）。尽管无法制备Mn类似物，但反式-MnBr2(dmpe)2和反式-Mnl2(dmpe)2都可以从各自的二卤化物获得。 MX2(dmpe)2(X = 卤化物) 化合物与 LiMe 或 MgMe2 进行烷基化，生成二甲基络合物 trans-MMe2(dmpe)2（M = V、Cr 或 Mn）；在这些条件下分离的钛配合物是反式TiMeCl(dmpe)2和反式TiMe2(dmpe)2的混合物，而获得的铁物质是顺式FeMe2(dmpe)2。磁化率和 E.S.R.测量结果表明，除卤化锰衍生物外，所有配合物均处于低自旋态，并且在通过 X 射线晶体学方法进行结构表征的那些配合物中观察到的金属-配体键长与所提出的基态构型一致。 MCl2(dmpe)2 物质和茂金属 M(η5-C5H5)2 的电子结构之间存在相似性，而 MMe2(dmpe)2 化合物类似于 M(η5-C5Me5)2。我们的研究表明，当电子数从 18 (Fe) 降低到 14 (Ti) 时，M-Me 基团的性质发生了逐渐变化。因此，钛配合物 trans-TiMe1.3Cl0.7(dmpe)2 似乎包含一个扭曲的甲基，由于将 C-H 键电子捐赠到金属上的空轨道中，涉及 Ti ⋯ H-C 相互作用。
The reaction of transition-metal dichlorides with 1,2-bis(dimethylphosphino)ethane (dmpe) leads to the brightly coloured, highly-crystalline octahedral complexes trans-MCl2(dmpe)2(M = Ti, V, Cr, or Fe). Although the Mn analogue could not be prepared, both trans-MnBr2(dmpe)2 and trans-Mnl2(dmpe)2 can be obtained from the respective dihalides. Alkylation of the MX2(dmpe)2(X = halide) compounds with either LiMe or MgMe2 leads to the dimethyl complexes trans-MMe2(dmpe)2(M = V, Cr, or Mn); the titanium complex isolated under these conditions is a mixture of trans-TiMeCl(dmpe)2 and trans-TiMe2(dmpe)2, while the iron species obtained is cis-FeMe2(dmpe)2. Magnetic susceptibility and e.s.r. measurements indicate a low-spin state for all the complexes except the manganese halide derivatives, and metal–ligand bond lengths observed in those complexes structurally characterised by X-ray crystallographic methods are consistent with the proposed ground-state configurations. There is a similarity between the electronic structures of the MCl2(dmpe)2 species and the metallocenes M(η5-C5H5)2, while the MMe2(dmpe)2 compounds resemble M(η5-C5Me5)2. Our studies indicate a progressive change in the nature of the M–Me groups upon lowering the electron count from 18 (Fe) to 14 (Ti). Thus, the titanium complex trans-TiMe1.3Cl0.7(dmpe)2 appears to contain a distorted methyl group involving a Ti ⋯ H–C interaction due to donation of C–H bond electrons into an empty orbital on the metal.