Tetrabenzoporphyrin precursor

Matsuo Y, Sato Y, Niinomi T, Soga I, Tanaka H, Nakamura E (2009) Columnar structure in bulk heterojunction in solution-processable three-layered p-i-n organic photovoltaic devices using tetrabenzoporphyrin precursor and silylmethyl[60]fullerene. J Am Chem Soc 131 16048-16050. doi 10.1021/ja9048702... 

The ideal monomer for the synthesis of a symmetrically substituted tetrabenzoporphyrin by an analogous tetramerization would be expected to be the isoindole 96. This substance has not been prepared, but the expectation of its usefulness is confirmed by the observation that 1,3,4,7-tetra-methylisoindole is an excellent precursor, in spite of the fact that it appears to be structurally unsuitable in that it has one a-methyl group too many. Thus, heating 1,3,4,7-tetramethylisoindole with nickel(II) acetate in 1,2,4-trichlorobenzene under reflux provides the nickel(II) octamethyltetra-benzoporphyrin (97) in 71% yield.123 The transition metal ion has a template effect since without it only a small amount (5%) of the metal-free tetrabenzoporphyrin is formed. Various other metal complexes (Mg, Mn, Fe, Co, Cu) have been made this way.123 124 An alternative route involves fusing the... 

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