UV-laser photoisomerization of fumaryl chloride - The first identificationof maleoyl chloride: matrix isolation infrared and ab initio studies

Fourier transform infrared spectra of fumaryl chloride 1 isolated in an arg on matrix at 10 K have been analyzed. The comparison between the ab initio HF/6-31G calculated infrared spectra with the experimental ones reveals the existence of three planar conformers, the cis-cis la, the cis-trans Ib and the trans-trans Ic, Laser UV irradiation of 1 at lambda = 340 nm yields ma leoyl chloride 2 by a carbon carbon double bond photoisomerization process. The first identification of this compound was performed by comparison of t he experimental infrared spectra with the calculated ones at the MP2/6-1G** level. AMI semiempirical and ab initio calculations were used to calculate the structure and the relative stability of the three non planar maleoyl c hloride conformers. (C) 2000 Elsevier Science B.V. All rights reserved.