Efficient Computational Methods for Accurately Predicting Reduction Potentials of Organic Molecules

Document Type

Article

Publication Date

6-26-2008

Publication Source

Journal of Physical Chemistry A

Volume Number

112

Issue Number

25

First Page

5684

Last Page

5690

Publisher

American Chemical Society

ISSN

1089-5639

Abstract

A simple computational approach for predicting ground-state reduction potentials based upon gas phase geometry optimizations at a moderate level of density functional theory followed by single-point energy calculations at higher levels of theory in the gas phase or with polarizable continuum solvent models is described. Energies of the gas phase optimized geometries of the S0 and one-electron-reduced D0 states of 35 planar aromatic organic molecules spanning three distinct families of organic photooxidants are computed in the gas phase as well as well in implicit solvent with IPCM and CPCM solvent models. Correlation of the D0 − S0 energy difference (essentially an electron affinity) with experimental reduction potentials from the literature (in acetonitrile vs SCE) within a single family, or across families when solvent models are used, yield correlations with r2 values in excess of 0.97 and residuals of about 100 mV or less, without resorting to computationally expensive vibrational calculations or thermodynamic cycles.

Keywords

Quantum mechanical calculations, Ground State Reduction Potentials, Photooxidants, Polarizable Continuum Model, IPCM, CPCM, Solvent Models, Gas Phase Calculations, Electron Affinity

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