Sensitized singlet oxygen luminescence

Gorman, A.A., Hamblett, I., Lambert, C., Prescott, A.L., Rodgers, M.A.J., and Spence, H.M. (1987) Aromatic ketone naphthalene systems as absolute standards for the triplet sensitized formation of singlet oxygen, 02(1Ag), in organic and aqueous-media-A time-resolved luminescence study, J. Am. Chem. Soc., 109, 3091-3097. 

Several luminescent Os" and Irin complexes, including [Os(bipy)3]2+, have been used as singlet oxygen sensitizers.85... 

SINGLET OXYGEN DIMOL-SENSITIZED LUMINESCENCE AND REACTIONS OF SINGLET OXYGEN WITH ORGANOMETALLICS... 

Luminescence of organic chromophores sensitized by energy transfer from singlet oxygen has also been reported for many years. " Several mechanisms have been suggested for this luminescence. 

We now report time-resolved and steady-state measurements of phthalocyanine luminescence sensitized by singlet oxygen dimols, produced both by photosensitization and by thermal processes the detailed kinetics strongly support Scheme 2. 

The data are consistent with the mechanism in scheme 2, in which the 700 nm luminescence is a result of energy transfer to Pc from dimol. This mechanism predicts that if dimol formation does not lead to 02 quenching and the lifetime of dimols is much less than of monomols, the Pc-sensitized dimol luminescence should depend quadratically on the singlet oxygen concentration, and the lifetime of the 700 nm luminescence should be half that at 1270 nm, as observed. 

The data suggest that activated dimol luminescence is a universal phenomenon which can be observed in solvents of widely varying nature and can be surprisingly efficient. This type of sensitized luminescence may account for the wide distribution of red luminescence often attributed to singlet oxygen dimol emission in biological and other systems. 

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