THEORETICAL-STUDY OF CP2TI(H)(SIH3) AND CP2TISIH2 AND THEIR POSSIBLE ROLE IN THE POLYMERIZATION OF PRIMARY ORGANOSILANES
THEORETICAL-STUDY OF CP2TI(H)(SIH3) AND CP2TISIH2 AND THEIR POSSIBLE ROLE IN THE POLYMERIZATION OF PRIMARY ORGANOSILANES
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DOI：
10.1021/om00118a002
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发表时间：
1990-04-01
期刊：
影响因子：
2.8
通讯作者：
TSCHINKE, V
中科院分区：
文献类型：
--
作者：
HARROD, JF;ZIEGLER, T;TSCHINKE, V
Baerends等人利用密度泛函理论和HFS-LCAO程序系统模拟了Cp 2 Ti（H）（SiH 3）-* Cp 2 Ti = SiH 2 + H2和Cp 2 Ti = SiH 2 + SiH 4-*·Cp 2 Ti（H）SiH 2SiH 3两个反应，研究了这些反应的动力学和热力学特征，计算结果表明，第一反应可以在Ca的中等活化势垒下进行。60 kJ moT 1和焓约。40 kJ mol-1。发现第二反应是放热的（约-100 ℃）。48 kJ moT 1），激活势垒约为。12 kJ mol-1。先前提出的机制为二茂钛催化的脱氢偶联的有机硅烷的评价在这些计算方面，它的结论是，α-氢化物消除硅烷加成路线是可行的。还计算了每个重要反应中间体的结构和热力学参数。
The two reactions Cp2Ti (H)(SiH3)—* Cp2Ti= SiH2+ H2 and Cp2Ti= SiH2+ SiH4—*• Cp2Ti (H) SiH2SiH3 have been modeled with use of density functional theory and the HFS-LCAO program system by Baerends et al. Both kinetic and thermodynamic features of these reactions were studied, and the results of the computations indicate that the first reaction can proceed with a moderate activation barrier of ca. 60 kJ moT1 and an enthalpy of ca. 40 kJ mol-1. The second reaction is found to be exothermic (ca.-48 kJ moT1) with an activation barrier of ca. 12 kJ mol-1. The previously proposed mechanism for the titanocene-catalyzed dehydrocoupling of organosilanes is evaluated in terms of these calculations, and it is concluded that the a-hydride elimination-silane addition route is viable. The structural and thermodynamic parameters for each of the important reaction intermediates are also calculated.