Article In: orcid, cienciavitae

Kinetic study of formation/dissociation of Cu(II) and Zn(II) complexes of cyclen macrocyclic ligand with pendant thiol group

Polyhedron

Ševcíková, Romana; Lubal, Premysl; Santos, Isabel — 2013 — Elsevier

Key information

Authors:

Ševcíková, Romana; Lubal, Premysl; Campello, Maria Paula Cabral (Maria Paula Cordeiro Crespo Cabral Campello Aboim de Barros); Santos, Isabel (Isabel da Graça Rego dos Santos)

Published in

October 2013

Abstract

The kinetic properties of macrocyclic ligand 2-[1,4,7,10–tetraazacyclododecane-1-yl]-ethanethiol (L1, DOSH) were studied with Cu(II) and Zn(II) metal ions, using conventional molecular absorption spectroscopy in pH regions 2.5–4.7 and 4.3–6.0 for Cu(II) and Zn(II), respectively. The obtained partial rate constants, measured at 25 °C and ionic strength I = 0.1 M (KCl), are slightly lower than for parent cyclen (1,4,7,10-tetraazacyclododecane) macrocyclic ligand supporting the hypothesis that the thiol pendant arm is not directly involved in the formation of these metal complexes. The study of the dissociation of the copper(II)-L1 complex in the presence of perchloric acid and at higher temperatures (75–95 °C) showed that this complex is more kinetically inert than the copper(II) complex with cyclen, indicating that the presence of the thiol pendant arm plays a key role as protecting group of copper(II) ion. On contrary, the dissociation of zinc(II) complex in presence of copper(II) ion measured at laboratory temperature (25 °C) and in 0.1 M-solution of hydrochloric acid is going via the metal-exchange reaction mechanism. Altogether, these findings show that L1 ligand presents favorable kinetic properties for further conjugation with biomolecules, aiming at their use in medicinal chemistry.

Publication details

Authors in the community:

Publication version

AO - Author's Original

Publisher

Elsevier

Link to the publisher's version

https://www.sciencedirect.com/journal/polyhedron

Title of the publication container

Polyhedron

First page or article number

268

Last page

273

Volume

62

ISSN

0277-5387

DOI

10.1016/j.poly.2013.06.052

WoS (Web of Science)

WOS:000324226200032

Fields of Science and Technology (FOS)

chemical-sciences - Chemical sciences

Keywords

  • Macrocyclic ligands
  • Cyclen derivatives
  • Thiol group
  • Copper/zinc complexes
  • Formation/dissociation kinetics
  • Rate constants
  • Radiopharmaceuticals

Publication language (ISO code)

eng - English

Alternative identifier (URI)

http://dx.doi.org/10.1016/j.poly.2013.06.052

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