Molecular Structures of Cis- and Trans-1, 2-Dichloroethene: A Real-Time Gas Electron Diffraction and AG Initio Study

摘要

The molecular structures of cis- aand trans-1,2-dichloroethene were studied in the gas phase by electron diffraction, using our new real-time data acquisition technique. For cis-dichloroethene the structural parameters are (r sub a distances (Angstroms) and angles (deg), with 3sigma in parentheses): C-C1:1.717(2); C=C:1.337(4); C1-C=C: 124.0(2); and H-C=C:120.3(3). For trans-dichloroethene: C-C1:1.725(2); C=C:1.332(8); C1-C=C:120.8(6); and H-C=C:124.0(3). The experimental work was augmented by ab initio gradient geometry refinements of the two compounds and of cis- and trans-difluorothene. The 4-21G, 5-31G**, and 3-3-21G basis sets were used in various series of calculations. Without any exception, the calculated structural trends for the cis- and trans-configurations are in excellent agreement with the experiments.