Outer-sphere charge transfer photochemistry

Distinct from other transitions, the energy of the OSCT bands depends on medium parameters in the case of CTTS such parameters as solvent nature and its polarity, composition of the solution, and temperature should be considered. 

Usually, the products of the CTTS excitations are solvated electrons and oxidized substrates  

This photochemical mode is observed in the case of electron-rich metal centres ligated by poor electron acceptors cyanide complexes, eg [Fen(CN),J4, [Run(CN)6]4 , [Moiv(CN)8]4, and [ WIV(CN)S]4 are known as the most efficient in the eMlv production. A typical reaction is photo-oxidation of hexacyanoferrate(II)  

When two associated ions are coordination compounds, the IPCT transitions may lead to charge transfer between both centres, between ligands of the two complexes, and between metal and ligand of different complexes [11]. 

A second sphere interaction may result in quenching of the CT excited states by energy transfer processes, leading to luminescence quenching, eg the MLC I Re bpy luminescence of Re1 monomeric and polymeric complexes is quenched by Cu11 species and the sacrificial electron donor 2,2, 2 -nitrilotriethanol (TEOA) [95]. 

---

Vogler, A., Kunkeley, H. Photochemistry of Transition Metal Complexes Induced by Outer-Sphere Charge Transfer Excitation. 158, 1-30 (1990). 

Vogler A, Kunkeley H (1990) Photochemistry of Transition Metal Complexes Induced by Outer-Sphere Charge Transfer Excitation. 158 1 - 30 Volkert WAJurisson S (1996) Technetium-99m Chelates as Radiopharmaceuticals. 176 123-148 Vondenhof M, see Mattay J (1991) 159 219-255 VoyerN (1997) The Development of Peptide Nanostructures. 184 1-38 Waldmann H, see Sauerbrei B (1997) 186 65 - 86 Walter C.see FessnerW-D (1997) 184 97-194 Wan P, see Krogh E (1990) 156 93-116... 

Photochemistry of Transition Metal Complexes Induced by Outer-Sphere Charge Transfer Excitation... 

Vogler A, Kunkely H. Outer-sphere charge transfer in ion pairs with hydridic, carbani-onic, sulfidic and peroxidic anions as electron donors - spectroscopy and photochemistry. Coord Chem Rev 2002 229 147-52. 

---