Phosphorescence from metalloporphyrins

Porphyrins and certain metalloporphyrins are excellent photosensitizers because of similar energies of the singlet and triplet excited levels, high intersystem crossing yield and long triplet lifetimes. The triplet state energies of M(Por) are estimated to be 159-193 kJmor from their phosphorescence spectra. The acceptor can be a variety of other species e.g. - Oj ), por-... 

Metalloporphyrins constitute an important family of complexes which frequently emit from porphyrin IL states [13, 126, 184]. The characterization of emitting IL states outlined above also applies to metalloporphyrins and related complexes. For example, since zinc exerts only a moderate heavy atom effect, zinc porphyrins show an IL fluorescence at r. t. and a relatively long-lived phosphorescence at 77 K [185,186],e.g.,... 

In contrast, the luminescence of metalloporphyrin dyes originates from the tetrapyrrolic macrocycle, but it is greatly affected by the nature of the central metal ion coordinated by the porphyrin ring and by axial ligands. Pt " - and Pd -porphyrins are particularly interesting because of their bright short-decay phosphorescence at room temperatures, and practically no fluorescence. They... 

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