Structure and bonding of d8 allyl complexes M(η3-allyl)L3 (M = Co, Rh, Ir;: L = phosphine or carbonyl)
Structure and bonding of d8 allyl complexes M(η3-allyl)L3 (M = Co, Rh, Ir;: L = phosphine or carbonyl)
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DOI：
10.1021/om050257b
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发表时间：
2005-07-18
期刊：
影响因子：
2.8
通讯作者：
Lin, ZY
中科院分区：
文献类型：
--
作者：
Ariafard, A;Lin, ZY
用密度泛函理论方法研究了d(8)五配位烯丙基配合物M(eta(3)-烯丙基)L-3(M=Co，Rh，Ir；L=膦或羰基)的结构和成键。在这些拟平方锥形d(8)配合物中，我们发现只有外结构对应于势能面上的能量极小值。外结构能够最大限度地促进金属(D)到烯丙基(pi*)的反键作用。计算结果表明，Ir和Co络合物的内键结构是两种不同外键结构相互转化的过渡态。只有膦配位的Ir(eta(3)-allyl)(PMe3)(3)等配合物的金属-烯丙基键作用最强，而Co(eta(3)-allyl)(CO)(3)等只含羰基的配合物的相互作用最弱。我们还研究了烯丙基配体的ETA(3)->；ETA(3)->；ETA(3)和ETA(3)->；ETA(1)->；ETA(3)重排，发现这两种重排机理对于本文所研究的d(8)配合物在能量上都是可行的。
Density functional theory calculations were used to study structure and bonding of d(8) five-coordinate allyl complexes M(eta(3)-allyl)L-3 (M = Co, Rh, Ir; L = phosphine or carbonyl). In these pseudo-square-pyramidal d(8) complexes, we found that only the exo structures correspond to energy minima on the potential energy surface. The exo structures are able to maximize the metal(d)-to-allyl(pi*) back-bonding interaction. The calculations predicted that the endo structures for the Ir and Co complexes are transition states for interconversion of two different exo structures. Complexes such as Ir(eta(3)-allyl)(PMe3)(3) having only phosphines as the ancillary ligands possess the strongest metal-allyl bonding interaction, while complexes such as Co(eta(3)-allyl)(CO)(3) having only carbonyls have the weakest interactions. We also studied the eta(3) -> eta(3) ->eta(3) and eta(3) -> eta(1) -> eta(3) rearrangements of the allyl ligand and found that both the rearrangement mechanisms are energetically feasible for the d(8) complexes studied in this paper.