HEXAHYDROHEXAHELICENE - NON-PLANAR COMPOSITE MOLECULE WITH HIGHLY RESOLVED ELECTRONIC-SPECTRA IN A FROZEN NORMAL-ALKANE MATRIX

Quasilinear absorption, fluorescence and phosphorescence spectra of 7,8,8a,9,10,10c-hexahydrohexahelicene (HHHL) were obtained in a polycrystalline n-pentane matrix at 77 K. 1,2-dimethylnaphthalene fundamental vibration frequencies appear in the emission spectra of HHHL. No exciton splitting of lines in the electronic spectra of HHHL was detected. Both naphthalene units of the HHHL molecule, almost perpendicular to each other, are coupled very weakly. The phosphorescence to fluorescence quantum yield ratio is greater for HHHL than for naphthalene and amounts of 0.16. Multiplet structure of quasilinear HHHL spectra has been discussed. © 1979.