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Radical reactions in the co-ordinated sphere of transition metals. XIV—spin distribution of phenoxy radicals generated from biphenyldiols

✍ Scribed by P. Pelikán; A. Tkáč; L. Omelka; A. Staško

Publisher: John Wiley and Sons
Year: 1982
Tongue: English
Weight: 447 KB
Volume: 20
Category: Article
ISSN: 0749-1581
DOI: 10.1002/mrc.1270200403

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✦ Synopsis

Abstract

The phenoxy radicals obtained from 2,2′‐ and 4,4′‐biphenyldiols show, in nonpolar solvents, symmetrization of the unpaired electron spin density on the two phenyl rings in the temperature range 290–410 K. Below 270 K the paramagnetic systems became diamagnetic. This para‐diamagnetic conversion with temperature is reversible. According to INDO calculations the symmetrization of spin density is due to the formation of dimeric phenoxy radicals. The para‐diamagnetic conversion at various temperatures is explained by the reversible conversion of the radical dimer to the quinone‐hydroquinone pair.

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