PHOTOCHEMISTRY OF NONCONJUGATED BICHROMOP HORIC SYSTEMS .2. PHOTOCYCLIZATION REACTION AND FLUORESCENCE-SPECTRA STUDIES OF LONG-CHAIN BISCOUMARINS

A series of polymethylene bis (4-methyl-7-coumarinyl)oxyacetates have been synthesized and their photochemical reaction and fluorescence spe ctra have been studied. It was found that only intramolecular photocyc lization products were obtained when polymethylene his (4-methyl-7-cou marinyl)oxyacetates were directly irradiated in chloroform. The yields of the products decreased with the increase of methylene chain length s, and this result accords with the phenomena found in the fluorescenc e spectra, i.e., the relative fluorescence intensity increased with th e increase of methylene chain length.