Production and storage of multiple, photochemical redox equivalents on a soluble polymer

• Published in: Journal of the American Chemical Society Vol. 112; no. 21; pp. 7571 - 7578
• Main Authors: Worl, Laura A, Strouse, Geoffrey F, Younathan, Janet N, Baxter, Steven M, Meyer, Thomas J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.10.1990
• Subjects: 140505 - Solar Energy Conversion- Photochemical, Photobiological, & Thermochemical Conversion- (1980-); 360601 - Other Materials- Preparation & Manufacture; Applied sciences; CHEMICAL PREPARATION; CHEMICAL REACTIONS; COMPLEXES; DATA; ELECTRON TRANSFER; Exact sciences and technology; EXPERIMENTAL DATA; INFORMATION; MATERIALS SCIENCE; NUMERICAL DATA; OSMIUM COMPLEXES; PHOTOCHEMICAL REACTIONS; PHOTOSYNTHESIS; Physicochemistry of polymers; POLYMERS; Polymers and radiations; Properties and characterization; PYRIDYL RADICALS; RADICALS; RUTHENIUM COMPLEXES; SOLAR ENERGY; SYNTHESIS; TRANSITION ELEMENT COMPLEXES; Chemical solution; Electron transfer; Photoinduced effect; Visible spectrometry; Styrene derivative copolymer; Redox polymer; Lateral group; Preparation; Luminescence quenching; Osmium «II» Complexes; Kinetics; Ruthenium II Complexes; Styrene copolymer
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja00177a019

Soluble polymers have been prepared that contain high loadings of metal-to-ligand charge-transfer (MLCT) visible-light absorbers based on polypyridyl complexes of Ru{sup II} or Os{sup II}. The complexes have been attached to a styrene/chloromethylstyrene copolymer by nucleophilic displacement of the chloro groups. By using excesses of the complexes, complete substitution at the available {approximately} 30 chloro-methylated sites was achieved. A series of mixed-valence polymers with controlled M{sup III}/M{sup II} ratios has been prepared in acetonitrile or acidic aqueous solution by oxidation with Ce(IV). For the Os{sup II}-containing polymers, Os{sup II}*-based MLCT excited-state lifetimes and emission quantum yields are relatively unaffected by the Os{sup III}/Os{sup II} ratio. This shows that intramolecular oxidative quenching of Os{sup II*} by Os{sup III} is slow. The slow rate of electron-transfer quenching is a manifestation of the inverted region. Because excited-state properties are relatively unaffected in the mixed-valence polymers, it is possible to build up and store {approximately} 30 oxidative equivalents on individual polymeric strands by photochemical oxidation.