A quantum mechanical approach to the kinetics of the hydrogen abstraction reaction H2O2 + •OH → HO2 + H2O

✍ Scribed by F. Atadinç; H. Günaydin; A. S. Özen; V. Aviyente

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 215 KB
• Volume: 37
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.20102

✦ Synopsis

Abstract

The kinetics of the hydrogen abstraction from H~2~O~2~ by ^•^OH has been modeled with MP2/6‐31G*//MP2/6‐31G*, MP2‐SAC//MP2/6‐31G*, MP2/6‐31+G**//MP2/6‐31+G**, MP2‐SAC// MP2/6‐31+G**, MP4(SDTQ)/6‐311G**//MP2/6‐31G*, CCSD(T)/6‐31G*//CCSD(T)/6‐31G*, CCSD(T)/6‐31G**//CCSD(T)/6‐31G**, CCSD(T)/6‐311++G**//MP2/6‐31G* in the gas phase. MD simulations have been used to generate initial geometries for the stationary points along the potential energy surface for hydrogen abstraction from H~2~O~2~. The effective fragment potential (EFP) has been used to optimize the relevant structures in solution. Furthermore, the IEFPCM model has been used for the supermolecules generated via MD calculations. IEFPCM/MP2/6‐31G* and IEFPCM/CCSD(T)/6‐31G* calculations have also been performed for structures without explicit water molecules. Experimentally, the rate constant for hydrogen abstraction by ^•^OH drops from 1.75 × 10^−12^ cm^3^ molecule^−1^ s^−1^ in the gas phase to 4.48 × 10^−14^ cm^3^ molecule^−1^ s^−1^ in solution. The same trend has been reproduced best with MP4 (SDTQ)/6‐311G**//MP2/6‐31G* in the gas phase (0.415 × 10^−12^ cm^3^ molecule^−1^ s^−1^) and with EFP (UHF/6‐31G*) in solution (3.23 × 10^−14^ cm^3^ molecule^−1^ s^−1^). © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 502–514, 2005