Inorganic Chemistry, Vol.35, No.22, 6406-6412, 1996
Photodriven Electron and Energy-Transfer from Copper Phenanthroline Excited-States
Electron and energy transfer from copper 1,10-phenanthroline excited states is observed at room temperature in organic solvents. The copper phenanthroline excited states are metal-to-ligand charge-transfer in nature and have lifetimes of similar to 70-250 ns in dichloromethane solution if methyl or phenyl substituents are placed in the 2- and 9-positions of the phenanthroline ligand. The unsubstituted cuprous compound Cu(phen)(2)(PF6) is nonemissive under these conditions, and the excited state lifetime is <20 ns. The rate and efficiency of energy transfer to anthracene or electron transfer to viologens is reported. The cage escape efficiency of [Cu(dpp)(2)(2+), MV(+.)], where dpp is 2,9-diphenyl-1,10-phenanthroline, is close to unity within experimental error. Back electron transfer to ground slate products occurs at the diffusion limit 2 x 10(10) M(-1) s(-1).
Keywords:DPP = 2;9-DIPHENYL-1;10-PHENANTHROLINE;CAGE ESCAPE YIELDS;PHOTOPHYSICAL PROPERTIES;INORGANIC EXCIPLEXES;METAL-COMPLEXES;PHOTO-REDUCTION;SYSTEMS;BIS(2;9-DIMETHYL-1;10-PHENANTHROLINE)COPPER(I);PHOTOCHEMISTRY;WATER