13C–H coupling constants as a tool in tautomerism studies of 1,2,3-triazole, 1,2,4-triazole, and tetrazole

Abstract

Comparison of one or two bond ¹³C–H coupling constants of azoles and their N-methylated derivatives indicates that 1,2,3-triazole, like pyrazole, in concentrated solutions exists as a cyclic associate, whereas 4-methyl-1,2,3-triazole, 1,2,4-triazole, and tetrazole are linearly associated, like imidazole. Similar results were obtained using ¹³C–H couplings of azole–acetone adducts as reference. The results agree with other trends in physical properties.