ESR and theoretical study of tetrathiofulvalene and dibenzotetrathiofulvalene and their radical cations

The three semi‐empirical methods MNDO, AM1 and MINDO/3 have been used to determine geometries, ionization potentials and spin densities of tetrathiofulvalene, dibenzotetrathiofulvalene and their radical cations. ESR measurements of the cation radicals both in solution and the solid states provided experimental spin densities. A comparison is made between calculated and experimental data; it appears that MINDO/3 is superior for the calculation of spin densities.