1,2-Diiododisilane and 1,1,2,2-tetraiododisilane: gas-phase molecular structure and conformational composition as determined by electron diffraction
作者:Eirik Røhmen、Kolbjørn Hagen、Reidar Stølevik、Karl Hassler、M. Pöschl
DOI:10.1016/0022-2860(91)80146-u
日期:1991.4
Abstract The molecular structures of 1,2-diiododisilane (DIDS) at 55°C and 1,1,2,2,-tetraiododisilane (TIDS) at 155°C have been studied using gas-phase electron diffraction data. These molecules exist as mixtures of anti and gauche conformers. The observed conformational compositions were (percentage of gauche ): 76(16) % for DIDS, and 60 (29%) for TIDS. Assuming Δ S = R ln 2, the conformational energy differences
摘要 已使用气相电子衍射数据研究了 55°C 下 1,2-二碘乙硅烷 (DIDS) 和 155°C 下 1,1,2,2,-四碘乙硅烷 (TIDS) 的分子结构。这些分子作为反和 gauche 构象异构体的混合物存在。观察到的构象组成为(gauche 的百分比):DIDS 为 76(16)%,TIDS 为 60(29%)。假设 Δ S = R ln 2,构象能差 δ E ( gauche-anti ) 为:-0.3 (DIDS) 和 +0.2 (TIDS),误差极限为 ±0.6 kcal mol-1。1,2-二碘乙硅烷的键长 ( rg ) 和价角 (< α ) 估计值为 2 σ 不确定度:r (SiSi)=2.380(34)A, r(SiI)=2.429(13)A , ∠ISiSi=107.5(1.2)°,φ(gauche)=58(31)°。对于 1,1,2,2-四碘二硅烷,我们发现