The evaluation of bond dissociation energies for NO₂ scission in nitro compounds using density functional and complete basis set methods

By using the density functional theory (B3LYP) and four highly accurate complete basis set (CBS-Q, CBS-QB3, CBS-Lq, and CBS-4M) ab initio methods, the X(C, N, O)--NO_2 bond dissociation energies (BDEs) for CH_3NO_2, C_2H_3NO_2, C_2H_5NO_2, HONO_2, CH_3ONO_2, C_2H_5ONO_2, NH_2NO_2 (CH_3)_2NNO_2 are computed. By comparing the computed BDEs and experimental results, it is found that the B3LYP method is unable to predict satisfactorily the results of bond dissociation energy (BDE); however, all four CBS models are generally able to give reliable predication of the X(C, N, O)--NO_2 BDEs for these nitro compounds. Moreover, the CBS-4M calculation is the least computationally demanding among the four CBS methods considered. Therefore, we recommend CBS-4M method as a reliable method of computing the BDEs for this nitro compound system.