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

Fourier transform infrared spectra of fumaryl chloride 1 isolated in an argon 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 maleoyl chloride 2 by a carbon carbon double bond photoisomerization process. The first identification of this compound was performed by comparison of the 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 chloride conformers. (C) 2000 Elsevier Science B.V. All rights reserved.