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.
Joshi
Ravi
R
Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
Ghanty
Tapan K
TK
Naumov
Sergej
S
Mukherjee
Tulsi
T
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