PYRAMIDAL DISTORTION OF THE NO2 GROUP IN THE RADICAL ANION OF 2,4,6-TRIMETHOXYNITROBENZENE
L. A. Shundrin
N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Division, Russian Academy of Sciences
Keywords: radical anions, hyperfine coupling, structural distortions, nitrobenzene, nitro group
Abstract
Electrochemical reduction in DMF is used to produce the radical anion of 2,4,6-trimethoxynitrobenzene with an EPR spectrum that shows hyperfine splitting for 15N nuclei of the nitro group and 13С nuclei of the benzene ring given the natural abundance of the isotopes. According to UB3LYP/6-31+G* quantum chemical calculations considering solvation in the PCM model, the nitro group in the equilibrium conformation of the RA of 2,4,6-trimethoxynitrobenzene is rotated relative to the benzene ring plane by an angle close to 90° and has a pyramidal structure. The calculated isotropic hyperfine coupling constants for this conformation are closest to the experimental results.
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