Inorganic Chemistry, Vol.37, No.11, 2756-2762, 1998
Preparation and photophysical properties of amide-linked, polypyridylruthenium-derivatized polystyrene
The polymer poly(4{2-[N,N-bis(trimethylsilyl)amino]ethyl}styrene), prepared by anionic polymerization and of low polydispersity (M-w/M-n = 1.10-1.18), has been derivatized by amide linkage to [Ru-II(bpy)(2)(4-(CO-)-4'-CH3-bpy)-](2+) (bpy is 2,2'-bipyridine; 4-(CO-)-4'-CH3-bpy is 4-carbonyl-4'-methyl-2,2'-bipyridine). Unreacted amine sites were converted into acetamides by treatment with acetic anhydride to give derivatized polymers of general formula [PS-CH2CH2NHCO(Ru-n(II),Me-m)](PF6)(2n), where m + n = 11, 18, or 25, PS represents the polystyrene backbone, and Ru-II and Me present the attached complex and acetamide, respectively. Spectral and electrochemical properties of the derivatized polymers are similar to those of the model [Ru(bpy)(2)(4-CONHCH2CH2C6H5-4'-CH3-bpy)](2+) (4-CONHCH2CH2C6H5-4'-CH3-bpy is 4'-methyl-2,2'-bipyridinyl-4-(2-phenylethylamide)), but emission quantum yields (phi(em)) and time-resolved emission decays are slightly dependent on the level of Ru-II loading, with nonexponential, irradiation-dependent decays appearing at high loadings. The decays could be fitted satisfactorily to the first derivative of the Williams-Watts distribution function. These results are discussed with reference to possible structural and multichromophoric effects on excited-state decay.
Keywords:DIELECTRIC RELAXATION BEHAVIOUR;ANIONIC LIVING POLYMERIZATION;EMPIRICAL DECAY FUNCTION;N-ETHYLATED COPOLYMERS;WATER-SOLUBLE POLYMER;ENERGY-TRANSFER;ELECTRON-TRANSFER;EXCITED-STATE;POLYPYRIDINE COMPLEXES;PHOTOINDUCED ELECTRON