Reaction of BX(2)-BX(2) (X=H or OH) with M(PH3)(2) (M=Pd or Pt). A theoretical study of the characteristic features
Reaction of BX(2)-BX(2) (X=H or OH) with M(PH3)(2) (M=Pd or Pt). A theoretical study of the characteristic features
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DOI：
10.1021/ic951504e
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发表时间：
1997-01-15
影响因子：
4.6
通讯作者：
Kikuno, T
中科院分区：
文献类型：
--
作者：
Sakaki, S;Kikuno, T
插入M（PH 3）（2）（Nd = Pd或Pt）转化为BX（2）-BX（2）（X = H或OH）进行了理论研究，采用从头算MO/MP4 SDQ、SD-CI和双取代偶合簇合物（CCD）方法，MP4 SDQ方法提供了与SD-CI和CCD方法相似的活化能（E（a））和结晶度（E（exo（MP4 SDQ值在这里给出）。对于X = OH和M = Pt，该反应以类似于15 kcal/mol的中等E（a）和类似于20 kcal/mol的相当大的E（exo）进行，对于X = H和M = Pt，该反应以20 kcal/mol的较高E（a）和33 kcal/mol的较高E（exo）进行，II应当注意，8-B键以及Si-Si键，比C-C键更容易进行Pt（PH 3）2的插入反应，然而，Pd（PH 3）（2）插入到B（OH）（2）-B（OH）（2）中是困难的，不同于插入到Si-Si键中，Pt-BH 2和Pt-B（OH）（2）键能估计为类似于60 kcal/mol，类似于Pt-SiH 3键能并且远大于Pt-CH 3键能，而Pd-B（OH）（2）键能（49 kcal/mol）远小于Pt-B（OH）（2）键能。BX（2）-BX（2）反应具有有趣的特征;在过渡态（TS）附近，不仅B-B键的σ * 轨道，而且未被占据的π和π * 轨道都可以与Pt的被占据的d（σ）和d（π）轨道形成电荷转移相互作用，这使得TS稳定。这就是为什么尽管B-B键比Si-Si键强得多，Pt（PH 3）（2）很容易插入BX（2）-BX（2）中。
The insertion of M(PH3)(2) (Nd = Pd or Pt) into BX(2)-BX(2) (X = H or OH) was theoretically investigated with the ab initio MO/MP4SDQ, SD-CI, and coupled cluster with double substitutions (CCD) methods, The MP4SDQ method provides an activation energy (E(a)) and an exothermicity (E(exo)) similar to those of the SD-CI and CCD methods (the MP4SDQ values are given here). This reaction proceeds with a moderate E(a) of similar to 15 kcal/mol and a considerable E(exo) of similar to 20 kcal/mol for X = OH and M = Pt and a higher E(a) of 20 kcal/mol and a higher E(exo) of 33 kcal/mol for X = H and M = Pt, II should be noted that the 8-B bond, as well as the Si-Si bond, undergoes the insertion reaction of Pt(PH3)2 much more easily than does the C-C bond, However, the insertion of Pd(PH3)(2) into B(OH)(2)-B(OH)(2) is difficult, unlike the insertion into the Si-Si bond, The Pt-BH2 and Pt-B(OH)(2) bond energies were estimated to be similar to 60 kcal/mol, being similar to the Pt-SiH3 bond energy and much greater than the Pt-CH3 bond energy, while the Pd-B(OH)(2) bond energy (49 kcal/mol) was calculated to be much smaller than the Pt-B(OH)(2) bond energy. The reaction of BX(2)-BX(2) exhibits interesting features; around the transition state (TS), not only the sigma* orbital of the B-B bond but also the unoccupied pi and pi* orbitals can form the charge-transfer interaction with the occupied d(sigma) and d(pi) orbitals of Pt, which stabilizes the TS, This is the reason that although the B-B bond is much stronger than the Si-Si bond, the insertion of Pt(PH3)(2) into BX(2)-BX(2) easily occurs.