Novel photosensitizers for the E/Z-isomerization of trienes. Part 2. Mechanistic and photophysical aspects

Abstract

To investigate the reaction mechanism, the disodium salts of o-(6-hydroxy-3-oxo-3H-xanthen-9-yl)benzenesulphonic acid and its thioxanthene analogue were selected from a class of photosensitizers firstly applied to the E/Z-isomerization of trienes. As an example of the latter the conversion of tachysterol into previtamin D was chosen. A presentation of the photophysical properties of six sensitizers with xanthene, thioxanthene and selenoxanthene moieties and a description of the aggregation phenomena of the above-mentioned two compounds completes this study.