Regioselective syntheses of 2,3-disubstituted-12-formyl-5,10,15,20- tetraphenylporphyrins and their metal complexes

Regioselective synthesis of 2,3-dibromo-12-formyl-5,10,15,20- tetraphenylporphyrin, H2TPPBr2(CHO) was achieved by bromination of H2TPP(CHO) as the precursor. The Suzuki/Stille coupling reaction of H2TPPBr2(CHO) produced good yields of various H2TPPR2(CHO) (R = phenyl, 2-thienyl and phenylethynyl) derivatives. These porphyrins and their metal complexes were characterized by electronic absorption, 1H NMR and mass spectroscopic methods. MTPPR2(CHO) derivatives showed marked change in their absorption spectral features in contrast to their corresponding MTPP(CHO) complexes. The crystal structures of ZnTPP(CHO)(CH3OH)·0. 5(C7H8) and H2TPP(Ph)2(CHO) exhibited more of saddle distortion combined with varying degree of ruffled and wave distortions of their macrocyclic rings as evidenced from the normal coordinate structure decomposition analysis. © 2010 World Scientific Publishing Company.