亚烷基卡宾与亚烷基锂氟类卡宾化学键结构的量子拓扑研究

Quantum Topological Study on the Structure of Chemical Bonds in Alkylidenecarbene and Lithio-Fluoro-Carbenoid

用ab initio(3-21G)方法对亚烷基卡宾H_2C—C的单线态及三线态结构进行了电子密度拓扑分析,说明了它们的亲电、亲核反应方向,讨论了亚烷基锂氟类卡宾H_2C—CLiF的4种构型,论证了该分子中不存在四元环结构、Li—C键以静电作用为主的特性,并预测了加成反应机理。

The structure and properties of singlet and triplet alkylidenecarbene, H2C = C , were studied with topological analysis of electronic charge density at ab initio(3-21G) level. The orientations of electrophilic and nucleophilic reactions can be explained on this basis. As for lithio-fluo-ro-carbenoid, H2C = CLiF, four equilibrium geometries were studied. The results show that in carbenoid species, Li and H atoms did not form a chemical bond, there is no four-membered-ring in the molecule, and electrostatic interaction is dominant in Li-C bond. The mechanism for addition reaction of carbenoid would be predicted.