Preparation and Properties of Two Tris o-Semiquinone Complexes

Dennis G. Brown* and W. Leo Johnson, III Department of Chemistry University of Idaho Moscow, Idaho, U. S. A. Z. Naturforsch. 34b, 712-715 (1979); received January 9, 1979 Semiquinone, Iron, Chromium Tris o-benzosemiquinone complexes of iron and chromium are reported. These complexes contain three 3,5-di-£-butyl-o-semiquinato ligands and a tri valent metal ion. The iron complex can be obtained from either the more highly oxidized o-quinone or reduced catechol dianion precursor. The coordinated o-semiquinone ligand is surprisingly stable. A simple infrared criterion is suggested for detecting the presence of a coordinated o-semiquinone.