Technetium(V) and rhenium(V) oxo complexes of a peptide having a KYC-sequence such as KYCAR (H3L5) and KYCAREPPTRTNAYWGQG-NH2 (H3L18) were synthesized, and structures of the complexes were characterized by spectroscopic techniques. All of the complexes were synthesized by the ligand exchange reaction of [(n-C4H9)4N] [MOCl4] (M = 99Tc, Re) with peptide in methanol or dimethylformamide solution. These complexes have a square pyramidal structure with an oxo ligand at the apical position. The peptide is coordinated to a metal atom through N(amine) of lysine, S(thiol) of cysteine, and N(amide) of tyrosine and cysteine in the equatorial plane. A lysine (CH2)4NH2 group of the L5 ligand has the syn conformation with respect to metal-oxo bonding in the complex. The syn isomer was selectively formed in the ligand exchange reaction. The conversion of the syn isomer to the anti isomer was observed only for syn-[ReO(L5)], in which the coordination of water to the trans position of the oxo ligand was involved.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry