Conformational analysis of unsaturated molecules: 1,4-cis-dichlorobutene-2

Infrared and Raman spectra have been obtained for 1,4 cis-dibromobutene-2 in the liquid, amorphous and crystalline phases. Normal coordinate calculations have been performed for several model conformations. These data show the SCS and SCS' conformations as the more stable isomers. The two isomers are seen to be of nearly equal energies on the basis of empirical nonbonded-atom calculations,In the crystalline state only one isomer (probably SCS) is found.