Generation of reactive oxygen species by photolysis of the ruthenium(II) complex Ru(NH3)5(pyrazine)2+ in oxygenated solution. |
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| Authors: | Roberto Santana da Silva Mario Sergio P Marchesi Antonio Claudio Tedesco Alexander Mikhailovsky Peter C Ford |
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| Institution: | Faculdade de Ciências Farmacêuticas de Ribeir?o Preto, Universidade de S?o Paulo, Av. do Café s/n, CEP 14040-903, Ribeir?o Preto, SP, Brazil. silva@chem.ucsb.edu |
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| Abstract: | Metal-to-ligand charge transfer photolysis of the ruthenium(II) pyrazine complex Ru(NH3)5pz2+ (I) in pH 7.4 oxygenated phosphate buffer solution generates the Ru(III) analog Ru(NH3)5pz3+ plus the reactive oxygen species singlet oxygen and superoxide. Based on the very short MLCT lifetime (re-measured as approximately 250 ps in D2O) of I* and the quantum yield for singlet oxygen formation (0.01 for aerated D2O) the rate constant for oxygen quenching of I* was calculated to be approximately (3+/-1)x10(10) M-1 s-1. |
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