Syntheses and characterization of porphyrins and their zinc complexes appending a multi-dentate ligand

Porphyrins with a multi-dentate ligand have been prepared by a covalent binding of nitrilotriacetic acid (NTA) to meso-mono (ortho- or para-aminophenyl)-triphenylporphyrin. The equilibrium between the porphyrins and Zn2+ has been analyzed by ultra violet–visible (UV–Vis) and 1H NMR spectroscopies and the porphyrins are found to form complexes with porphyrin/zinc ratios of 1:1 and 1:2. The zinc complexes with the porphyrin/zinc ratios of 1:1 and 1:2 have been prepared and characterized by UV–Vis, infrared (IR) and 1H NMR spectroscopies. An accelerated zinc incorporation reaction into the porphyrin appending NTA at its ortho-phenyl group is reported.