Photochromism of Hemithioindigo Derivatives. I. Preparation and Photochromic Properties in Organic Solvents

Article abstract of DOI:10.1246/bcsj.65.649

Thirteen hemithioindigo (HT) derivatives bearing alkyl chains are newly synthesized and their photochromism and emission properties are investigated.The Z/E photoisomerisms of these compounds in organic solvents are essentially in agreeement with data reported by Mostoslavskii and Izmail'skii (J.Gen.Chem.USSR, Engl Transl.), 31, 21 (1961), and subsequent papers).At 77 K both the E and Z isomers of HT chromophore emit fluoresscences of comparable intensities, whereas at room temperature very weak fluorescence is observed only from the Z isomer.Examination of repeatable numbers of Z/E photoisomerization reveals that the HT chromophore possesses remarkable inherent photofatigue resistance.