NATURE OF THE 9,9'-BIANTHRYL AND 10,10'-DIMETHOXY-9,9'-BIANTHRYL RADICAL-ANIONS

Electrochemically generated 9,9'-bianthryl (BA) and 10,10'-dimethoxy-9,9'-bianthryl (DA) radical anions have been studied by means of UV-VIS and ESR spectroscopy. The electronic absorption spectra as well as ESR studies indicate that within the electrochemically generated radical anions the unpaired electron is localized on one of both anthracene subunits of the A-A parent molecule. The rate constants for the intramolecular electron exchange reactions within the radical anions A-A-. were measured by ESR line-broadening effects. In dimethylformamide rate constants of (4.2 +/- 0.3) x 10(7) s-1 and (2.2 +/- 0.3) x 10(7) s-1 were found for BA-. and DA-. at 298 K respectively. The rates have been interpreted in terms of Marcus electron transfer theory and it was found that the reactions are strongly nonadiabatic. Theoretical calculations verify these circumstances.