Theoretical studies of C-NH2 bond dissociation energies for some amino compounds

In this paper, quantum chemical calculations are used to estimate the equilibrium C-NH2 bond distances and bond dissociation energies (BDEs) for 21 amino compounds. These compounds are studied by employing the hybrid density functional theory (B3LYP, B3PW91, B3P86) methods and the complete basis set (CBS-Q) method together with the 6-311G** basis set. In order to test whether the non-local BLYP method suggested by Ref. [B.S. Jursic, J. Mol. Struct. (Theochem), 366 (1996) 103. [21]] is general for our study and whether the DFT method has a low basis sets sensitivity, the BDEs for 6 amino compounds are also calculated using BLYP/6-31+g* and B3P86 method with 6-31+g*, 6-31+g** and 6-311+g** basis sets for comparison. The obtained results are compared with the available experimental results. It is demonstrated that the non-local BLYP method is not suitable for our amino compound system. While, B3P86 and CBS-Q methods are accurate for computing the reliable BDEs for amino compounds. Considering the inevitably computational cost of CBS-Q method, B3P86 method may be more suitable to produce reasonable BDEs of C-NH2 bond for amino compounds