The electronic origin of geometrical deformations in cyclohexadienyl and cyclobutenyl transition metal complexes
The electronic origin of geometrical deformations in cyclohexadienyl and cyclobutenyl transition metal complexes
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环己二烯基和环丁烯基过渡金属配合物几何变形的电子起源
DOI：
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发表时间：
1976
期刊：
影响因子：
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通讯作者：
P. Hofmann
中科院分区：
文献类型：
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作者：
R. Hoffmann;P. Hofmann
本文提出了一个环己二烯- M（CO）_3络合物（M = Fe ~+，Mn，Cr ~-）中饱和碳原子离面弯曲的电子因素的例子。在环己二烯基配体超共轭扩展非键MO波函数的亚甲基氢。CH 2氢对MO的贡献是这样的，当C6 H7配体与M（CO）3基团结合时，会产生二级M-CHz相互作用，这是不稳定的。在环丁烯基和环辛三烯基络合物中，这种相互作用是缺乏的，因此这些络合物应该比环己二烯基络合物更少弯曲。类似的分析使环戊二烯-Fe（CO）3络合物中远离金属的弯曲、环戊二烯酮络合物中的减少以及富烯或环戊二烯基碳离子络合物中朝向金属的弯曲合理化。检查了C6 H、M（CO）3复合物中的电荷分布和取代基效应，以及苄基-M（CO）3中假设的异构体的情况。
A case is presented for an electronic factor in the out-of-plane bending of the saturated carbon in cyclohexadienyl- M(CO)3 complexes, M = Fe+, Mn, Cr-. In the cyclohexadienyl ligand hyperconjugation extends the nonbonding MO wave function to the methylene hydrogens. The phase of the CH2 hydrogen contributions to that MO is such that when the C6H7 ligand is bound to the M(C0)3 group there arises a secondary M-CHz interaction which is destabilizing. In cyclobutenyl and cyclooctatrienyl complexes this interaction is lacking and thus these should be less bent than cyclohexadienyl complexes. A similar analysis rationalizes the bending away from the metal in cyclopentadiene-Fe(C0)3 complexes, its lessening in cy- clopentadienone complexes, and the bending toward the metal in fulvene or cyclopentadienyl-carbonium ion complexes. The charge distribution and substituent effects in C6H,M(CO)3 complexes are examined, as well as a case of hypothetical isom- erism in benzyl-M(C0)3.