Porphyrin core, donor periphery

The design of dendritic multiporphyrin systems [18] permits energy transfer over longer distances. The outer shell of the dendrimer shown in Fig. 5.14 is made up of eight porphyrin-zinc complexes as energy donor units. Excitation of the units of the outer shell leads to fluorescence emission of the metal-free porphyrin core as a result of energy transfer from the periphery to the energy acceptor [19]. 

A water soluble version of this system with eight AF-343 TPA donor chromophores and a core acceptor porphyrin was also been produced (Scheme 41) [111]. Water solubiUty was achieved by inclusion of tri(ethylene glycol) (TEG) moieties in the periphery of the dendrimer. Although oxygen luminescence could not be observed upon TPE (lex = 780 nm) in D2O solution, when the solvent was changed to benzene-ds. weak emission was observed under TPE conditions. 

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