Abstract: | The H‐bonded complexes formed from interaction between NH2NO (NA) and H2O2 (HP) have been investigated by using B3LYP and MP2 methods with a wide range of basis sets. We found six H‐bonded complexes in which three of them have cyclic structure. Calculations carried out at various levels show that the seven‐membered cyclic structure with O···HO and O···HN hydrogen bonding interactions is the most stable complex. The large binding energy obtained for A1 complex probably results from a more linear arrangement of the O···H N and O H···OH‐bonds in the seven‐membered structure A1. The natural bond orbital (NBO) analysis and the Bader's quantum theory of atoms in molecules have been used to elucidate the interaction characteristics of the NA‐HP complexes. The NBO results reveal that the charge transfer energy corresponds to the H‐bond interactions for A1 complex is grater than other complexes. The electrostatic nature of H‐bond interactions is predicted from QTAIM analysis. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 |