Abstract
The equations and the mutual relations pertinent to the energetics of sequential electrooxidation and reduction steps were formulated from the points of view of the Born-Haber-type thermodynamic energy cycle and SCFMO calculations. Dependence of half-wave reduction potentials on increasing conjugation was discussed on the basis of the above equations and the symmetry of molecular orbitals. Combining the above treatments with the theory of electronic spectra the general equations have been derived for describing the mutual relation between oxidation-reduction potentials and electronic spectra. Further, the theoretical treatment was extended to the energetics of the electrooxidation and reduction process in excited states. The electron-transfer interaction between an electron donor and an electron acceptor has been considered in photoexcited states by virtue of oxidation and reduction potentials. Our treat ment provided theoretical background for the Rehm-Weller equation on the electron transfer interaction in photoexcited states. Finally, hydrophobi c and electron donor-acceptor interactions of electrogenerated active species were elucidated. The stronger inclusion of the anion radicals were observed for the dicyanobenzene anion radical-cyclodextrin complexes, being explained in terms of their dipole-induced dipole interaction. On the other hand the strong hydrogen-bonding of the electrogenerated p-quinone dianions with CH3OH was well explained in terms of the strong n-σ type charge-transfer interaction.
