الفهرس 
Historical overview on the photochemical properties and applications of ruthenium complexesOnly 14 pages are availabe for public view
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Abstract
Photophysical properties of a series of ruthenium (II) phenanthroline derivatives were studied in aqueous medium. 3MLCT excited state energy, E0-0, was found to be in the range 215±1 KJmol-1 except for [Ru(DPPhen)3]2+ where E0-0 is about 209.0 KJmol-1. The oxidation potential of the current series of sensitizers was in the range from 1.05 V vs. SCE in case of [Ru(TMPhen)3]2+ to 1.47 V vs. SCE in case of [Ru(NPhen)3]2+. Oxygen quenching rate constants, kq, were found to be in the range 1.02 × 109 M-1s-1 for [Ru(NPhen)3]2+ to 4.83 × 109 M-1s-1 for [Ru(TMPhen)3]2+ and were found to decrease as the oxidation potential of the sensitizer increases. On the other hand, the efficiency of singlet oxygen production did not show the familiar correlation with the oxidation potential as that shown for aromatic compounds. The parameter, pCT, were estimated for each sensitizer and found to be about 0.84±0.05 except for [Ru(NPhen)3]2+ where pCT value of 0.355 was used for good evaluation of the calculated kq only. It has been found that the experimental values of kq and calculated values of kD increase as pCT increases. Data treatment shows a charge transfer character of the excited exciplexes 3(T1..3) and 1(S0..1) of about 35.3%. The mechanism of quenching of the excited charge transfer states such as 3MLCT by molecular oxygen and singlet oxygen thereby produced is much more complicated than with organic sensitizers since more variables are participating simultaneously, such as excited state energy, nature of the excited state, oxidation potential of the sensitizer, spin orbit coupling constant of the central metal in addition to the steric factors imposed by the structural nature of the ligands. Therefore, the exact mechanism of oxygen quenching
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of the excited states of coordination compounds will not become clear till all these variables are considered and carefully studied