Intramolecular ligation of carbonyl oxygen to central zinc in synthetic oligopeptide-linked zinc-porphyrins

Article abstract of DOI:10.1246/bcsj.67.2478

Oligopeptide-linked zinc-porphyrins were prepared (oligopeptide = -Phe(m)-Ala(n)-OMe and porphyrin = 5,15-diaryl-2,3,7,8,12,13,17,18-octaethylporphyrin). ¹H NMR, IR, visible, and CD spectra of the synthetic molecule in a chlorinated methane (CDCl₃ or CH₂Cl₂) showed that the carbonyl oxygen of the N-terminal amino acid of the linked peptide should ligate the central zine metal in the molecule as the axial ligand to form a pentacoordinated zinc-porphyrin. The coordination of the zinc with the peptide framework changed the optical and electrical properties, indicating that such ligation might control the reactivity in biological metallotetrapyrrole-protein systems as well as the coordination to the peptide residue.