The structures of the complexes generated by hexamethylenetetramine and nitric acid have been fully optimized by B3LYP method at the 6-311＋＋G＊＊ and aug-cc-pVTZ levels. The intermolecular hydrogen-bonding interactions have been calculated by the B3LYP/6-311＋＋G＊＊, B3LYP/aug-cc-pVTZ, MP2（full）/6-311＋＋G＊＊ and CCSD（T）/6-311＋＋G＊＊ methods, respectively. The NBO （nature bond orbital）, AIM （atom in molecule）, temperature effect and solvation effect have been analyzed to reveal the origin of the interactions. The results indicate that the stable hydrogen-bonded complexes could be generated by hexamethylenetetramine and nitric acid. The interactions follow the order of （a）（e）（b）（c）（d）（f）（g）. The C–N bonds which are adjacent to the methylene involving the hydrogen bonds tend to break in the chemical reaction. Due to the exothermic process, low temperature is conducive to the formation of the composition, which tallies with the experimental result.
The adsorption of CH3CN and CH3NC on the Pt(111)surface at the 1/4 monolayer(ML)coverage has been carried out at the level of density functional theory for understanding hydrogenation processes of nitriles.The most favored adsorption structure for CH3CN is the C-N bond almost parallel to the surface with the C-N bond interaction with adjacent surface Pt atoms.For CH3NC,the most stable configuration is the CH3NC locates at the face center cubic(fcc)site with the C-atom bonded to three Pt atoms.In addition,the HCN and HNC adsorption has been computed,and the adsorption pattern is nearly similar to the CH3CN and CH3NC,respectively.The adsorbed molecules rehybridize on the surface,becoming non-linear with a bent C-C-N or C-N-C angle.Furthermore,the binding mechanism of these molecules on the Pt(111)surface is also analyzed.
