Ionized state of hydroperoxy radical-water hydrogen-bonded complex: (HO2-H2O)+.
Ab initio molecular orbital calculations have been employed to characterize the structure and bonding of the (HO2-H2O)+ radical cation system. Geometry optimization of this system was carried out using unrestricted density functional theory in conjunction with the BHHLYP functional and 6-311++G(2df,2p) as well as 6-311++G(3df,3p) basis sets, the second-order Møller-Plesset perturbation (MP2) method with the 6-311++G(3df,3p) basis set, and the couple cluster (CCSD) method with the aug-cc-pVTZ basis set. The effect of spin multiplicity on the stability of the (HO2-H2O)+ system has been studied and also compared with that of oxygen. The calculated results suggest a proton-transferred hydrogen bond between HO2 and H2O in H3O3+ wherein a proton is partially transferred to H2O producing the O2...H3O+ structure. The basis set superposition error and zero-point energy corrected results indicate that the H3O3+ system is energetically more stable in the triplet state; however, the singlet state of H3O3+ is more stable with respect to its dissociation into H3O+ and singlet O2. Since the resulting proton-transferred hydrogen-bonded complex (O2...H3O+) consists of weakly bound molecular oxygen, it might have important implications in various chemical processes and aquatic life systems.
Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
Ravi
R
Joshi
Tapan K
TK
Ghanty
Sergej
S
Naumov
Tulsi
T
Mukherjee
D000838:Anions / Q000737:chemistry*; D002412:Cations / Q000737:chemistry*; D003198:Computer Simulation; D006860:Hydrogen Bonding; D008958:Models, Molecular; D010100:Oxygen / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
D000838:Anions; D002412:Cations; D017382:Reactive Oxygen Species; D014867:Water; D010100:Oxygen