Identification of the Different Mechanisms of Activation of a [RuII(tpy)(bpy)(OH2)]2+ Catalyst by Modified Ruthenium Sensitizers in Supramolecular Complexes

• Published in: Journal of physical chemistry. C 2013-05, Vol.117 (19), p.9605-9612
• Main Authors: Herrero, Christian, Quaranta, Annamaria, Fallahpour, Reza-Ali, Leibl, Winfried, Aukauloo, Ally
• Format: Article
• Language: English
• Subjects: Catalytic methods; Chemistry; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; General and physical chemistry; General, apparatus; Materials science; Methods of nanofabrication; Organic compounds; Physics; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Surface physical chemistry
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp4025816

We report the synthesis and photophysical studies of two different complexes incorporating a chromophore and a catalyst within the same structure. The chromophores used are of the form [(bpy)2(phen)RuII]2+ and [(COOEt)2bpy)2(phen)RuII]2+. The electron-withdrawing auxophores in the periphery of the bipyridine ligands convey the chromophores with different chemical and photophysical properties. The catalyst incorporated is [RuII(tpy)(bpy)(OH2)]2+ which has been shown to carry out the catalytic oxidation of water and organic substrates. We present the different mechanisms of light-driven activation observed for the catalyst. Depending on the electronic properties of the chromophores, these can act as antenna systems by activating the catalyst via energy transfer followed by electron transfer to an acceptor or as chromophores, in which case activation of the catalyst is done by direct electron transfer from the photo-oxidized sensitizer. The oxidized form of the catalyst formed by either mechanism is stable on a time scale of milliseconds.