SYNTHESES AND SPECTRA OF SOME INERT TRIPHENYLMETHYL DIRADICALS - A CONCURRENT DIRADICAL FORM

The synthesis and characterization of 11 inert diradicals of the perch lorotriphenylmethyl class, -6-Cl-4(C6Cl5)C-C6Cl4-Sp-C6Cl4-C(C6Cl5)-C6C l4-R(p) where R is Cl, OH, or O- and Sp is a spacer chain from zero to nine atom links, are described. The ESR spectra of these species in s olution from room temperature to -140 degrees C (glassy matrix) point to the concurrence of two isomeric diradical forms: the conventional s pecies, displaying spin-spin dipolar interaction, and a form apparentl y devoid of it. The ESR C-13 hyperfine couplings, the magnetic suscept ibility, and the IR and UV-vis spectra of these diradicals are describ ed. Some related monoradicals and a triradical are also reported.