Molecular modeling of the influence of complex formation on the conformation and electronic absorption spectra of crown-containing styryl dyes

The conformation and electronic absorption spectra of crown-containing styryl dyes and their complexes with metal salts have been calculated. The long-wave absorption bands have been assigned. It was shown that the observed large hypsochromic shift of the absorption spectra during the formation of complexes of the cis-form of the dyes under consideration with alkaline earth ions is due to a change in the conformation of the chromophore and the resultant approximate prohibition with respect to symmetry of the long-wave electronic transition.Institute of Chemical Physics, Russian Academy of Sciences. Translated from Zhurnal Strukturnoi Khimii, Vol. 34, No. 2, pp. 39–45, March–April, 1993.