The photodimerisation of the alpha- and beta-forms of trans-cinnamic acid: a study of single crystals by vibrational microspectroscopy

Atkinson, S.D.M., Almond, M.J., Hollins, P. and Jenkins, S.L. (2003) The photodimerisation of the alpha- and beta-forms of trans-cinnamic acid: a study of single crystals by vibrational microspectroscopy. Spectrochimica Acta Part A, 59 (3). pp. 629-635. ISSN 1386-1425 doi: 10.1016/S1386-1425(02)00208-1

Abstract/Summary

Infrared and Raman microspectroscopy have been used to follow the photodimerisation reactions of single crystals, the alpha- and beta-forms of trans-cinnamic acid. This approach allows the starting materials and products -alpha-truxillic acid that has C-i symmetry and beta-truxinic acid, which has C-s symmetry-to be identified. It also allows the topotactic nature of the reaction to be confirmed. Attempts to produce the poorly-defined unreactive gamma-form of trans-cinnamic acid resulted only in a mixture of the alpha- and beta-forms. The findings suggest a wide role for these spectroscopic methods in monitoring solid-state organic reactions. (C) 2002 Elsevier Science B.V. All rights reserved.