Light harvesting and energy transfer within coumarin-labeled polymers

Linear copolymers that have pendant coumarin-2 and coumarin-343 chromophores were prepared as analogues to previously synthesized light-harvesting dendrimers. The chromophore ratios within these polymers were maintained similar to those of the various generation dendrimers to investigate the effect of polymer architecture on the energy-transfer efficiency between the coumarin-2 donors and coumarin-343 accepters. Both physical and photophysical properties of these polymers were analyzed and compared to those of the analogous dendrimers. Energy-transfer efficiencies were relatively high in the polymers; however, deleterious excimer formation between the coumarin-343 chromophores diminished the quantum yield of fluorescence of the polymers when compared to the analogous dendrimers. Overall, it was found that the ultimate performance of the dendritic light-harvesting antennae was superior to that of the polymeric analogues, but the polymers were more practical in terms of synthetic accessibility. (C) 2001 John Wiley & Sons, Inc.