Intra-polymer photosensitized charge separation using a series of ruthenium(II) complex and viologen-containing polymers

Abstract

Spectroscopic and thermal properties of a series of ruthenium(II) complex and viologen-containing polymers based on poly( 1-vinylimidazole) and partially quaternized poly( 1-vinylimidazole) and photosensitized charge separation using these polymers have been investigated. These polymers have the structures in which bis(2,2-bipyridine)rutneuium(II) complexes are coordinated with the imidazolyl residues and the alkyl viologen is covalently linked to the imidazolyl residue through a hexylene spacer on the same polymer backbone. These polymers have two maximum wavelengths in the luminescence spectra. 560 nm and 65() nm, which correspond to emissions of the ruthenium( II) complex residue compartmentalized by viologen residues and the alkyl side chains exposed to the bulk solution, respectively. The luminescence intensity at 560 nm decreases with decreasing viologen content. For photosensitized charge separation, the rates of viologen radical formation depend linearly on the initial concentration of the ruthenium(II) complex and viologen residue, indicating that the reactions proceed through an intra-polymer process.