Density functional calculations of the heats of formation for various aromatic nitro compounds

Isodesmic reactions of 18 aromatic nitro compounds were selected in order to study their heats of formation at 298 K. Calculations were carried out by various density functional theories, together with different basis sets. The calculated heats of formation of 2-nitrotoluene, 3-nitrtoluene, 4-nitrotoluene, 2,4-dinitrotoluene, 2,5-dinitrotoluene, 2,6-dinitrotoluene, 2,4,6-trinitrotoluene, 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 2,6-dinitrophenol, 2,4,6-trinitrophenol, 2-nitroaniline, 3-nitroaniline, 4-nitroaniline, 2,4-dinitroaniline, and 2,6-dinitroaniline were averaged to be 8.61, 5.26, 4.89, 5.58, 5.84, 10.52, 10.32, -29.77, -24.67, -25.98, -29.16, -21.73, -18.32, 15.12, 18.17, 15.85, 14.04, and 14.60 kcal/mol, respectively. These values are very close to the experimental or multivariable linear regression results. (C) 2003 Elsevier B.V. All rights reserved.