Computational study of radical cations of saturated compounds with sigma-type and pi-type N-N bonds

Geometrical and electronic properties have been calculated and are compared with experimental data for three saturated diaza compounds and their radic al cations and dications. The molecular geometries in the different oxidati on states are consistently reproduced very well using the B3PW91 and B3LYP three-parameter density functional methods, with a modest 6-31G* basis set. The performance of the pure density functionals BLYP and BPW91 is less sat isfactory. The Hartree-Fock method yields excellent results in some cases b ut poor results in others. Ionization potentials and electron-nuclear hyper fine interactions are reproduced moderately well with B3LYP and B3PW91. Ele ctronic excitation energies calculated with time-dependent density function al theory agree very well with experiment in most cases. For 2,7-diazatetra cyclo[6.2.2.2(3,6).0(2,7)]tetradecane 2 and its radical cation and dication , the reorganization parameters for self-electron exchange were calculated and compared with experimental and earlier computed data. The calculations allow a good estimate of the different contributions to the energy barrier, i.e., the internal and solvent reorganization energies and the work term i n the case of 2+/2++.