Accession Number : AD0618963

Title :   ELECTRON SPIN RESONANCE STUDY OF P-PHENYLENE-DIAMINE POSITIVE ION,

Corporate Author : HARVARD UNIV CAMBRIDGE MASS DEPT OF CHEMISTRY

Personal Author(s) : Melchior ,M. T. ; Mali,A. H.

Report Date : 05 JUL 1960

Pagination or Media Count : 6

Abstract : The mono-positive radical ion of p-phenylene diamine was prepared by controlled potential electrolysis and studied by electron spin resonance. This ion was formed in acetonitrile solution with sodium perchlorate as supporting electrolyte and the controlled potential electrolysis was carried out in the microwave cavity of the ESR spectrometer. The ion exhibits a complex hyperfine structure in dilute solution; the observed spectrum consists of about 75 hyperfine components. Isotropic hyperfine coupling constants were assigned for the three types of interacting nuclei: the aromatic ring protons, amine protons, and the nitrogen nuclei. The large nitrogen hyperfine interaction observed is in marked contrast to Wurster's Blue cation, for which this interaction is vanishingly small. ESR spectra of deuterated derivatives were obtained and employed in making the assignment. The magnitude of the nitrogen hyperfine interaction relative to that of the amine protons is shown to be consistent with the mechanism of pi-sigma electron exchange interaction on the nitrogen atom. Electrochemical generation allows the study of the relatively unstable ion-radical, whereas other methods of preparation have been less successful. (Author)

Descriptors :   (*FREE RADICALS, MICROWAVE SPECTROSCOPY), (*AMINES, FREE RADICALS), (*MICROWAVE SPECTROSCOPY, FREE RADICALS), NUCLEAR MAGNETIC RESONANCE, IONS, ELECTROCHEMISTRY, HYPERFINE STRUCTURE, ORGANIC SOLVENTS, DEUTERIUM COMPOUNDS, AROMATIC COMPOUNDS

Distribution Statement : APPROVED FOR PUBLIC RELEASE