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Updated: May 19, 2026

Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
Published on: December 16, 2013
The coordination abilities of the multiHis-cyclopeptide with two metal-binding centers--potentiometric and
Aleksandra Kotynia1, Sylwia Bielińska, Wojciech Kamysz
1Department of Inorganic Chemistry, Wroclaw Medical University, Szewska 38, 50-139 Wroclaw, Poland.
Abstract:
In this paper we present the formation of mono- and binuclear complexes by the octapeptide (c(HKHPHKHP)) with copper(II) ions. The ligand was synthesized manually by the solid-phase method. Its characteristic cyclic structure significantly influences the coordination abilities. The studied peptide has two Pro amino acid residues in the sequence. This causes the formation of two independent centres able to undertake metal ion binding. The potentiometric and spectroscopic (UV-vis, CD and EPR) studies were carried out in aqueous solutions in the pH range 2.5-11.0 at 298 K, HNO(3) was used as the solvent with KNO(3), where the ionic strength was 0.1 M. The analysis of the potentiometric together with spectroscopic studies have shown that the investigated peptide forms only mono-nuclear complexes when the metal-to-ligand molar ratio is 1 : 1. When the concentration of Cu(ii) ions increases and the ligand-to-metal molar ratio is 1 : 2 the formation of binuclear complexes is preferred in the system.
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