卤代类卡宾结构和反应活性的理论研究(Ⅱ)——类卡宾CHClFLi的结构和稳定性  

Theoretical Studies on the Structures and Reactions of Halocarbenoids(Ⅱ) ——Structures and Stability of Carbenoid CHClFLi

作　　者：李吉海[1] 冯圣玉[1] 

机构地区：[1]山东大学化学院

出　　处：《高等学校化学学报》1998年第4期631-616,共1页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金

摘　　要：用从头算分子轨道理论，研究了不同卤代类卡宾ＣＨＣｌＦＬｉ的结构和稳定性．优化得到４种平衡构型和相应过渡态结构．对各构型的特点进行了分析。The structures and stabilities of the CHClFLi, as a model carbenoid substituted by two different halogenes, were first predicted by using ab initio theory. Four equilibrium geometries were optimized. Two σ complexes(geometries 1 and 2), formed by interaction of HOMO of singlet carbene HFC∶ with Li of LiCl, is close in energy and the most stable one. The three membered ring geometry(geometry 3), formed by interaction of HOMO and LUMO of singlet carbene HClC∶ with Li and F of LiF respectively, is “loose” in the structure and more unstable. Geometry 4 is a double three membered ring, and it is the most unstable one. The center carbon of those four geometries except 3 have positive charges, so the nuclophilic reaction of CHClFLi should be slower than that of CHCl 2 Li and CHBr 2Li. The transition states of geometries 2, 3 and 4 to 1 were given. The barriers of conversion are very little (1 76, 7 24, 1 53 kJ/mol). The four geometries are all more stable than their corresponding carbene(dissociation energies is 89 67, 87 11, 145 2, 50 11 kJ/mol respectively).

关 键 词：卤代 类卡宾 从头算 CHClFLi 结构 稳定性 

分 类 号：O623.221[理学—有机化学]