Generation of reactive oxygen species by photolysis of the ruthenium(II) complex Ru(NH3)5(pyrazine)2+ in oxygenated solution.
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.
da Silva
Roberto Santana
RS
Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café s/n, CEP 14040-903, Ribeirão Preto, SP, Brazil. silva@chem.ucsb.edu
Marchesi
Mario Sergio P
MS
Tedesco
Antonio Claudio
AC
Mikhailovsky
Alexander
A
Ford
Peter C
PC