Structure and bonding of H2O2 center dot center dot center dot X complexeswith (X = NO+, CN-, HCN, HNC, CO)

Accurate B3LYP and MP2 theoretical calculations, with the 6-311+G(3df,2p) b asis set, have been performed on different complexes, between hydrogen pero xide (HP) and NO+ (1), CN- (2-4), HCN (5-8), HNC (9-12) and CO (13 and 14). According to the binding energy obtained, the charged complexes (1-4) have large binding-energy values, yielding only cyclic stationary points. Howev er, the neutral complexes (5-14) showed medium to small binding-energy valu es with linear and cyclic arrangements, the cyclic structures being transit ion states and the linear complexes minima, on their corresponding PESs. Th e "atoms in molecules'' theory (AIM) was used to characterize the intermole cular interactions, ranging from electrostatic interactions for the HP ... NO+ complex (1) to different types of hydrogen bonding for 2 to 14. For all the structures, the binding energy was corrected for the BSSE by the count erpoise (CP) method. Moreover, calculations were performed also on the BSSE -corrected PESs.