ESR study of structural characteristics and intramolecular motions of tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine free radical in toluene

Abstract

The magnetic and dynamic properties of tris(2,6-di-tert-butyl-4-hydroxybenzyl)amine free radical was studied by ESR spectroscopy in the temperature range from 170 to 350 K in toluene. Symmetrical conformers in the rigid toluene matrix with characteristic angles θ1 = 26° and θ2 = 60° between the symmetry axis of the 2pz-orbital on the Cα atom of the phenoxyl ring and the direction of the Cα-Cβ bond of the CH2 fragment were determined. The activation energy of transition between the conformers was determined to be 8.2 kcal mol−1. The correlation time of transition between the conformers was established as 8.2·10−1 s.