Structural studies of triazolone and its N-methyl derivatives using infrared and Raman spectroscopy

The infrared and Raman spectra of triazolone, 4-methyl-triazolone, 1,4-dime thyl-triazolone and their deuterated homologues have been studied in the ra nge 4000 - 200 cm(-1). An assignment of fundamentals is given. The triazolo ne and 4-methyltriazolone exist in only one cetonic form, which is the same , in, both solid and dissolved states. The introduction of the C=O group in the 1,2,4-triazolic ring induces a decrease of the self association, compa red to other non N-substituted 1,2,4-triazoles. In, the dissolved state, th e NH group of 4-methyl-triazolone is submitted, as in the case of its thion e homologue, to an intermolecular interaction. The vNH...solvent frequency follows the increasing basicity of the solvents and gives evidence of a wea ker acidity of the oxygen derivative. The physical state effect on the CH g roup vibrations of the studied molecule:; have been explained by an inter-m olecular interaction CH...O=C in the solid state.