The infrared and Raman spectra of trans- and cis-tetrachloro-tetramethylbicylopropylidene

The title compounds trans- and cis-2,2,2',2'-tetrachloro-o-3,3.3',3'-tetramethyl-bicyclopopylidene were synthesized, and their infrared and Raman spectra were recorded. Non-coincidence between the IR and Raman bands of the trans compound suggested C-2h symmetry and a planar ring system. in the cis compound most of the IR and Raman bands coincided and a C-2v symmetry seems likely. The exocyclic C=C double bond gave rise to a medium/weak Raman band at 1847cm(-1) in the trans compound. In the cis derivative IR and Raman bands both at 1825 cm(-1) were observed. From similarities with related molecules. the ring breathing, the antisymmetric ring stretch, the CCl2 out-of-phase and in-phase stretch and the out-of-plane ring bending modes have been tentatively assigned for the trans and cis compounds. (C) 2008 Elsevier B.V. All rights reserved.