Synthesis and spectroscopic characterization of meso-tetra (Schiff-base substituted phenyl) porphyrins and their zinc complexes

In this work, a series of novel meso-tetra (Schiff-base substituted phenyl) porphyrins are reported from condensation of meso-tetra (p-aminopheny1) porphyrin with different substituted benzaldehydes. Their related zinc (II) complexes are also synthesized. These compounds have been characterized by spectroscopic determinations. Experimental results indicate that for the precursors, including meso-tetra (p-nitrophenyl) porphyrin and meso-tetra (p-aminophenyl) porphyrin, their substituted phenyls contribute obviously electronic effects on π-electron transition; while for meso-tetra (Schiff-base substituted phenyl) porphyrins, the secondary substituents in Schiff base groups provide weakly electronic effects on π-electron systems. These weak electronic effects are also observed in the electronic spectra of their zinc complexes. In fact the really electronic effect of secondary substituents should be considered as the contribution form the whole substituted phenyls in molecules of meso-tetra (Schiff-base substituted phenyl) porphyrin derivatives.

► Novel meso-tetra (Schiff-base phenyl) porphyrins were synthesized, and their zinc (II) complexes were also prepared.
► These compounds were well characterized by UV–Vis, IR, FL, and EPR determinations.
► The whole substituted phenyls in the Schiff base porphyrins should be considered as the secondary substituents.
► The electron donating effect from all substituted phenyls was stronger than the simple phenyl groups themselves.