Density functional study on the carbostannylation of aryne by the palladium(0)-iminophosphine catalyst. Does the apical site really contribute to the catalytic reaction?
Density functional study on the carbostannylation of aryne by the palladium(0)-iminophosphine catalyst. Does the apical site really contribute to the catalytic reaction?
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DOI：
10.1021/om0304053
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发表时间：
2003-10-13
期刊：
影响因子：
2.8
通讯作者：
Matsubara, T
中科院分区：
文献类型：
--
作者：
Matsubara, T
采用密度泛函方法（B3 LYP）研究了钯（0）-亚胺膦催化芳炔锡碳酰化反应的机理，并考虑了顶位的作用。计算表明，催化反应在两个可能的循环（循环A：1 --> 3 --> 1;循环B：1 --> 4 --> 1）中不是循环A而是循环B。发现顶端位是钯（0）-亚氨基膦络合物催化的起源。顶端位置的贡献降低了速率决定步骤的能垒，使催化反应成为可能。在循环B中，SnH（3）C与CH的Sn-C σ键断裂是一个速率决定步骤，它通过异裂机制进行，而没有Sn-C σ键与Pd的氧化加成（路径B）。然而，当Pd原子被Pt原子取代时，Sn-C σ-键的均裂与Pt的氧化加成（路径c）在能量上变得更有利。
The mechanism of carbostannylation of aryne by the palladium(0)-iminophosphine catalyst was examined using the density functional method (B3LYP) paying attention to the role of the apical site. The calculations showed that the catalytic reaction takes not cycle A but cycle B out of two possible cycles (cycle A: 1 --> 3 --> 1; cycle B: 1 --> 4 --> 1). It was found that the apical site is an origin of the catalysis of the palladium(0)-iminophosphine complex. The contribution of the apical site lowers the energy barrier of the rate-determining step and makes the catalytic reaction possible. The Sn-C sigma-bond breaking of SnH(3)Cequivalent toCH, which is a rate-determining step in cycle B, proceeds by the heterolytic mechanism without the oxidative addition of the Sn-C sigma-bond to Pd (path b). However, when the Pd atom is replaced by the Pt atom, the homolytic cleavage of the Sn-C sigma-bond with the oxidative addition to Pt (path c) becomes energetically more favorable.