title: Accurate calculation of absolute one-electron redox potentials of some para-quinone derivatives in acetonitrile.
abstract: Standard ab initio molecular orbital theory and density functional theory calculations have been used to calculate absolute one-electron reduction potentials of several para-quinones in acetonitrile. The high-level composite method of G3(MP2)-RAD is used for the gas-phase calculations and a continuum model of solvation, CPCM, has been employed to calculate solvation energies. To compare the theoretical reduction potentials with experiment, the reduction potentials relative to a standard calomel electrode (SCE) have also been calculated and compared to experimental values. The average error of the calculated reduction potentials using the proposed method is 0.07 V without any additional approximation. An ONIOM method in which the core is studied at G3(MP2)-RAD and the substituent effect of the rest of the molecule is studied at R(O)MP2/6-311+G(3df,2p) provides an accurate low-cost alternative to G3(MP2)-RAD for larger molecules.
authors.affiliation: Department of Chemistry, Yazd University, Yazd, Iran. namazian@rsc.anu.edu
authors.forename: Mansoor
authors.initials: M
authors.lastname: Namazian
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Coote
mesh_terms: D000097:Acetonitriles / Q000737:chemistry*; D000465:Algorithms; D004563:Electrochemistry; D004566:Electrodes; D004583:Electrons; D015394:Molecular Structure; D010084:Oxidation-Reduction; D011789:Quantum Theory; D011809:Quinones / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D000097:Acetonitriles; D011809:Quinones; D012996:Solutions; C032159:acetonitrile