Theoretical Study on σ-Bond Activation of (HO)2B−XH3 by M(PH3)2 (X = C, Si, Ge, or Sn; M = Pd or Pt). Noteworthy Contribution of the Boryl pπ Orbital to M−Boryl Bonding and Activation of the B−X σ-Bond
Theoretical Study on σ-Bond Activation of (HO)2B−XH3 by M(PH3)2 (X = C, Si, Ge, or Sn; M = Pd or Pt). Noteworthy Contribution of the Boryl pπ Orbital to M−Boryl Bonding and Activation of the B−X σ-Bond
复制标题
DOI：
10.1021/om990461x
复制
发表时间：
1999-10
期刊：
影响因子：
2.8
通讯作者：
S. Sakaki;S. Kai;M. Sugimoto
中科院分区：
文献类型：
--
作者：
S. Sakaki;S. Kai;M. Sugimoto
使用 MP2-MP4(SDQ) 和 CCSD(T) 方法从理论上研究了 (HO)2B−XH3 到 M(PH3)2（X = C、Si、Ge 或 Sn；M = Pd 或 Pt）的氧化加成。 (HO)2B−XH3 很容易氧化加成到 Pt(PH3)2，X = C 时具有中等活化能，X = Ge、Si 和 Sn 时势垒非常小或没有势垒。此外，(HO)2B-SiH3、(HO)2B-GeH3 和 (HO)2B-SnH3 在非常小的势垒或无势垒的情况下与 Pd(PH3)2 进行氧化加成。仅不能发生 (HO)2B−CH3 到 Pd(PH3)2 的氧化加成，但 (HO)2B−CH3 从 Pd(CH3)[B(OH)2](PH3)2 中的还原消除可以无障碍地发生。这些氧化加成的过渡态 (TS) 是非平面的，除了 (HO)2B−CH3 到 Pt(PH3)2 的氧化加成的近平面 TS 之外。这种TS结构对空间和电子因素非常敏感；例如，通过用 PH2(C2H5) 代替 PH3，TS 变得非平面，以减少 (HO)2B−CH3 和 PH2(C2H5) 之间的空间排斥。该机的一个值得注意的特点是...
Oxidative addition of (HO)2B−XH3 to M(PH3)2 (X = C, Si, Ge, or Sn; M = Pd or Pt) was theoretically investigated with MP2-MP4(SDQ) and CCSD(T) methods. (HO)2B−XH3 easily undergoes oxidative addition to Pt(PH3)2 with a moderate activation energy for X = C and either a very small barrier or no barrier for X = Ge, Si, and Sn. Also, (HO)2B−SiH3, (HO)2B−GeH3, and (HO)2B−SnH3 undergo oxidative addition to Pd(PH3)2 with either a very small barrier or no barrier. Only the oxidative addition of (HO)2B−CH3 to Pd(PH3)2 cannot take place, but the reductive elimination of (HO)2B−CH3 from Pd(CH3)[B(OH)2](PH3)2 occurs with no barrier. The transition states (TS) of these oxidative additions are nonplanar except for the nearly planar TS of the oxidative addition of (HO)2B−CH3 to Pt(PH3)2. This TS structure is very sensitive to steric and electronic factors; for instance, the TS becomes nonplanar by substituting PH2(C2H5) for PH3, to decrease the steric repulsion between (HO)2B−CH3 and PH2(C2H5). A noteworthy feature of the...