Porphyrin cores tetraphenyl porphyrins

High-temperature solution decomposition of Fe(TPP)N3 (TPP = tetraphenyl-porphyrin) in the absence of added base or oxygen has been examined. The only reaction product observed is formulated as (TPP)FeNFe(TPP), analogous to [Fe(TPP)]20.258 The structure of Fe(l-methylimidazole)2(PPIX),CH30H,H20 (PPIX = protoporphyrin IX) has been reported. The porphyrin has a distinctly ruffled inner core. Magnetic resonance studies of the autoreduction of ferric porphyrins in the presence of piperidine or cyanide demonstrate that reduction to iron(ii) is accompanied by one-electron oxidation of the substrate. ... 

Figure 13 Schematic representation of a family of dedrimers having a tetraphenyl porphyrin as a core and four identical dendronized wedges containing a variable number of zinc porphyrins. (Reprinted by permission of John Wiley Sons, Inc. from Ref. 31.)...

Zaleski and coworkers also prepared an interesting family of enediynes based on the porphyrin core [28]. These porphyrinic enediynes (Scheme 30.14) show systematic red shifts in their electronic spectra as a function of the number of conjugated alkyne units ( 13nm/alkyne), which indicate involvement of the enediyne units in the electronic excited states. Photochemical activation of the free base of tetraphenyl octakis(phenylethynyl) porphyrin derivative only led to the reduction of the porphyrin backbone via H-atom addition at the opposing me o-positions, suggesting significant activation barriers for the photo-BC. 

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