Photoinduced electron transfer transition metal ions

Most PET fluorescent sensors for cations are based on the principle displayed in Figure 10.7, but other photoinduced electron transfer mechanisms can take place with transition metal ions (Fabbrizzi et al., 1996 Bergonzi et al., 1998). In fact, 3d metals exhibit redox activity and electron transfer can occur from the fluorophore... 

A great variety of covalently or non-covalently boimd porphyrin-terpyri-dine motifs are known to closely mimic the initial photoinduced electron transfer (PET) or excitation energy transfer (EET) events of natural photosynthetic reactions. A first example of covalent connection of a terpyridine group to the axial position of a phosphorus porphyrin as in 33 (Fig. 26b) was presented by Kumar and Maiya [81 ]. The terpy moiety itself is a strong chelator towards other transition metal ions (see also 24). Upon postirradiation, the axial terpy subimits act as a donor and P(V) porphyrin as an acceptor. In fluorescence titrations it was found that the PET and EET reactions are mod-... 

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