二氯硅烯与乙烯和甲醛环加成反应机理的理论研究

用RHF/6-31G^*解析梯度方法研究了单重态二氯硅烯与乙烯和甲醛环加成反应的机理,并用二级微扰方法对各构型能量进行了相关能校正.结果表明,两反应历程均由两步组成:(1)二氯硅烯与乙烯和甲醛分别生成了中间配合物,是无势垒的放热反应;(2)中间配合物异构化成产物二氯硅杂环丙烷和二氯硅杂环氧甲烷,其势垒经零点能校正分别为97.43和103.29kJ/mol(MP₂/6-31G^*//6-31G^*).     

Dichlorosilylene and dichlorogermylene transfer to alkylidenephosphanes

The detection of Me₃GeSiCl₃, a product from the Si₂Cl₆ cleavage of trimethylgermylphosphanes, as a useful new source of SiCl₂ moieties, as well as new trapping reactions of SiCl₂ and GeCl₂ with functional alkylidenephosphanes (Me₃Si)₂CPX (X = halide or dialkylphosphanyl [PRR^′; R = i-propyl, R^′ = t-butyl]) are reviewed. In the primary step of the reactions, insertion into the P-X bond is competing with addition to the PC bond. SiCl₂ and GeCl₂ insertions are followed by dimerisation reactions leading to new highly functional P-phosphanylalkylidenephosphanes, that may rearrange to diphosphenes like (XCl₂Si)(Me₃Si)₂C-PP-C(SiMe₃)₂SiCl₂X (X = F, Cl, P-i-Pr₂) or (Cl₃Ge)(Me₃Si)₂C-PP-C(SiMe₃)₂GeCl₂PRR^′ or/and react further with SiCl₂ or GeCl₂. Reaction of (Me₃Si)₂CP-PRR^′ (R = i-propyl, R^′ = t-butyl) with Me₃GeSiCl₃ leads in a very selective fashion to a complete PC double bond cleavage by unique double SiCl₂ addition with formation of a stable P-phosphanylphosphadisiletane.