A vibrational study of tautomerism and associations of 2-mercaptoimidazole and 2-mercaptothiazole

Abstract

Infrared and Raman spectra of 2-mercaptoimidazole and 2-mercaptothiazole in solid state as well as i.r. spectra of 2-mercaptothiazole in HCCl3 and CS2 0.05M solutions have been investigated. A general assignment of all the observed bands is proposed for both fundamental vibrations and for overtone and combination bands. For 2-mercaptothiazole, the thiocarbonyl-form, intermolecularly hydrogen-bonded dimers in solid state, and unassociated molecules in dilute solutions of inert solvents have been established. Finally, based on this data, thermodynamic functions have been computed.