Quantum Chemical Investigation of the Electric Field Effect on Activation Barriers for Electrochemical Transformations of Organic Compounds

The MINDO/3 method was used to study the effect of intensity and vector direction of the external electric field on activation barriers of unimolecular reactions which are possible in electrochemical transformations of simple organic compounds:  orientation of molecules and radical anions, heterogeneous electron transfer to adsorbed molecules, dissociation of radical anions, cations, and molecules, inversion of anions, free radicals, and neutral molecules, cis−trans isomerization, and chair−boat conformational transition in molecules. The electronic and spatial structure of the molecules, free radicals, and ions, the height of the activation barriers of their reorientation, dissociation, isomerization, and conformational transition, and the configurational stability to change as affected by the field in the range 0.01−0.05 au are determined. Obtained data permit one to theoretically ground different effects under organic compound adsorption on the electrode surface, changes in stereochemistry of the products of alkyl halide electroreduction, and some properties of chemically modified electrodes possibly affected by electrode potential gradient.