Enthalpy of formation for indazoles (indazole, 1H-indazole-3-carboxylic acid, 1H-indazole-5-carboxylic acid, 1H-indazole-6-carboxylic acid and 1-methyl-1H-indazole-6-carboxylic methyl ester): experimental and theoretical studies.

The molar standard enthalpy of formation in condensed and gas phases of indazole, 1H-indazole-3-carboxylic acid, 1H-indazole-5-carboxylic acid, 1H-indazole-6-carboxylic acid and 1-methyl-1H-indazole-6-carboxylic methyl ester is reported. These properties were obtained indirectly from experimental determinations of the compounds using isoperibolic calorimetry and thermogravimetry. The values obtained for enthalpy of formation in the gas phase were compared with the computational results by means of the auxiliary density functional theory using deMon2k. The influence of the carbonyl and acetate groups on this type of compounds is analyzed energetically and structurally. The results obtained were compared and discussed with the data found in the literature. [ABSTRACT FROM AUTHOR]