Enthalpies and heat capacities of solution of 3,5-diamino-1,2,4-triazole and 3,5-diamino-1-phenyl-1,2,4-triazole in water

This paper focuses on the thermochemical behavior of two derivatives of 1,2,4-triazole which is often considered as a potential synthetic platform to develop novel antitumor or antimicrobial drugs, i.e., 3,5-diamino-1,2,4-triazole (compound 1) and 3,5-diamino-1-phenyl-1,2,4-triazole (compound 2). Experimental enthalpies of solution in water have been determined calorimetrically over the physiological temperature range. These quantities are used to compute standard enthalpies and heat capacities of solution. Standard partial molal heat capacities of solution are calculated from the heat capacities of solution and experimentally determined heat capacities of solid heterocycles. The results obtained are compared with those for hydrophilic urea and hydrophobic benzene and briefly discussed.