The reaction of silyl cyanide (R3SiCN) with hydrosilane (R′3SiH) in the presence of a catalytic amount of [(η5-C5H5)Fe(CO)2Me] formed R′3SiCN and R3SiH. This reaction involves Si–CN bond cleavage and provides a new method for the preparation of silyl cyanides. DFT calculation showed that coordinatively unsaturated [(η5-C5H5)Fe(CO)(SiMe3)] reacts exothermically with Me3SiCN to give the CN π-coordinated complex, [(η5-C5H5)Fe(CO)(η2-Me3SiCN)(SiMe3)], followed by exothermic silyl migration from the iron to the nitrogen atom of the η2-coordinated Me3SiCN with the activation energy of 8.8 kcal mol−1 to give [(η5-C5H5)Fe(CO)(Me3SiC=NSiMe3-κC,κN)]. The complex is one of the intermediates in the catalytic cycle. The related complex [(η5-C5Me5)Fe(CO)(κ-C,N-t-BuMe2SiC=NSiPh3)] was isolated in the reaction of [(η5-C5Me5)Fe(CO)(py)(SiPh3)] with t-BuMe2SiCN and characterized by 1H, 13C, and 29Si NMR spectroscopy. The activation energy of the Si–CN bond cleavage in [(η5-C5H5)Fe(CO)(κ-C,N-Me3SiC=NSiMe3)] was evaluated by DFT calculation to be 33.7 kcal mol−1 which is comparable to that in the reaction of acetonitrile (32.9 kcal mol−1).
叔丁基
氰化
硅(R3SiCN)与氢
硅烷(R′3SiH)在催化量的[(η5-
C5H5)Fe(CO)2Me]存在下反应形成了R′3SiCN和R3SiH。该反应涉及Si–CN键的断裂,并提供了一种制备
氰化
硅的新方法。DFT计算表明,配位不饱和的[(η5- )Fe(CO)(SiMe3)]与Me3SiCN发生放热反应,生成CN π-配位复合物[(η5- )Fe(CO)(η2-Me3SiCN)(SiMe3)],随后发生
铁原子向η2-配位Me3SiCN的氮原子的放热
硅迁移,活化能为8.8 kcal mol−1,生成[(η5- )Fe(CO)(Me3SiC=NSiMe3-κC,κN)]。该复合物是催化循环中的一个中间体。在[(η5-C5Me5)Fe(CO)(py)(SiPh3)]与t-BuMe2SiCN反应中,相关的复合物[(η5-C5Me5)Fe(CO)(κ-C,N-t-BuMe2SiC=NSiPh3)]被分离并通过1H、13C和29Si NMR光谱进行了表征。在[(η5- )Fe(CO)(κ-C,N-Me3SiC=NSiMe3)]中Si–CN键断裂的活化能通过DFT计算评估为33.7 kcal mol−1,且与
乙腈反应中的活化能(32.9 kcal mol−1)相当。