FROZEN-IN NON-EQUILIBRIUM ROTAMER MIXTURES IN 1,2-DIARYLETHYLENES OBTAINED BY LOW-TEMPERATURE IRRADIATION

Article abstract of DOI:10.1016/0022-2860(85)80160-5

trans-1,2-Di(2-naphthyl)-ethylene, formed in rigid media by UV irradiation of its cis isomer, comprises a mixture of three modifications, not in equilibrium with each other, that are tentatively assigned to the three possible rotamers.At somewhat lower viscosities, in the range 10⁸-10⁹ cP, equilibrium is established.Detection is by emission-spectroscopic methods.Three other related compounds showed only slight effects of the same kind.