E.s.r. evidence for a low-temperature distortion in the hexamethylbenzene radical cation
Abstract
The e.s.r spectrum of the radical cation of hexamethylbenzene at 77 K shows that the degeneracy of the ψA and ψS orbitals is lifted, since four strongly coupled methyl groups (11.5 G) and two weakly coupled methyl groups [(–)2.8 G] are observed; at 130 K, all six methyl groups become equivalent as a result of dynamic averaging of the hyperfine couplings.