The Electronic Spectra and Electronic Structures of Amino-substituted Benzenes

The electronic spectra and electronic structures of amino substituted benzenes have been studied by the semiempirical MO method, with the explicit inclusion of the electron repulsion. According to the calculated results, we can interpret the difference between the spectra of various poly-substituted aminobenzenes; also, the calculated excitation energies and oscillator strengths are in satisfactory agreement with the observed values. The relation between the present calculation and the simple Hückel MO calculation has been analyzed. Moreover, several interesting relations between the Hückel MO quantities of substituted benzenes and naphthalenes have been demonstrated and discussed. The calculated π-moment of aniline in the ground state is in satisfactory agreement with the experimental value. Furthermore, the π-moment of aniline in the lowest excited singlet state has been calculated and compared with the experimental value obtained from the measurement of the solvent shifts of the absorption and fluorescence spectra.