Accession Number : AD0618830

Title :   ELECTROCHEMICAL GENERATION OF FREE RADICALS AND THEIR STUDY BY ELECTRON SPIN RESONANCE SPECTROSCOPY; THE NITROBENZENE ANION RADICAL,

Corporate Author : HARVARD UNIV CAMBRIDGE MASS DEPT OF CHEMISTRY

Personal Author(s) : Geske,David H. ; Maki,August H.

Report Date : 27 OCT 1959

Pagination or Media Count : 6

Abstract : The nitrobenzene anion radical, (.C6H5NO2)(-), was prepared by constant potential electrolysis of nitrobenzene solutions at a mercury pool electrode placed directly inside the microwave cavity of an electron spin resonance spectrometer. Acetonitrile was used as a solvent with tetra-n-propylammonium perchlorate as supporting electrolyte. Well-resolved electron spin resonance spectra of the radical reduction product exhibit a hyperfine structure consisting of fifty-four components. Hyperfine coupling constants were assigned for the interaction of the unpaired electron with the various ring protons and the nitrogen nucleus. The odd electron distribution in the molecule is seen to be at least qualitatively in agreement with that predicted by conventional valence bond theory. The large hyperfine interaction with the nitrogen nuclear moment is presumed to arise from a sigma-pi exchange interaction on the nitrogen atom. Electrochemical generation in acetonitrile offers advantages over conventional alkali metal reductions in solvents such as tetrahydrofuran and 1,2-dimethoxyethane. (Author)

Descriptors :   (*NITROBENZENES, FREE RADICALS), (*FREE RADICALS, ELECTROCHEMISTRY), (*MICROWAVE SPECTROSCOPY, FREE RADICALS), NUCLEAR MAGNETIC RESONANCE, ABSORPTION SPECTRA, ELECTROLYSIS, ORGANIC SOLVENTS, ORGANIC NITROGEN COMPOUNDS, HYPERFINE STRUCTURE, CHEMICAL BONDS, NUCLEAR MOMENTS

Distribution Statement : APPROVED FOR PUBLIC RELEASE