Photochemical formation of thiirene and thioketene in 1,2,3-thiadiazoles with phenyl substituents studied by time-resolved spectroscopy

Authors:

• Gotard Tadeusz Burdziński,
• Michel Sliwa,
• Yunlong Zhang,
• Stéphanie Delbaere,
• Tomasz Pędziński,
• Julien Réhault

Abstract

Photochemistry of 4-phenyl-1,2,3-thiadiazole (PT) and 4,5-diphenyl-1,2,3- thiadiazole (DPT) in solution was studied at room temperature using UV-vis and IR transient absorption spectroscopies (λ_ex = 266 nm). Ultrafast techniques show a very fast rise (<0.3 ps) of thiirene and thioketene species, formed from 1,2,3-thiadiazoles in the singlet excited state. The remarkable unimolecular stability of thiirenes in solution is observed. On a millisecond time scale thiirenes with phenyl substituents undergo an intermolecular reaction (dimerization of thiirene-thioketene complexes) leading to 1,3-dithiole derivatives. © 2013 The Royal Society of Chemistry and Owner Societies.