Density functional study of the nitrosamine-formic acid and nitrosamine-formamide interactions

During the computation, 15 complexes for nitrosamine-formic acid (Z, E), and nitrosamine-formamide were found. For all of the methods, containing B3LYP/6-311++(2d,2p), B3LYP/aug-cc-pVDZ and B3LYP/aug-cc-pVTZ, the complexes of Z-1 and F-1 are the most stable ones. The order of hydrogen bond strengths are as follows: O-H⋯O > N-H⋯O > N-H⋯N > C-H⋯O > C-H⋯N. Results show that the proton stretching between a donor and an acceptor affects the strength of hydrogen bond. In some cases, eight-member ring is formed due to the resonance-assisted hydrogen bonds (RAHB) mechanism. AIM analyses at the hydrogen bond critical points show maximum electron density (ρ) for O-H⋯O, and minimum electron density for C-H⋯O.