J 2018

Optimization of the selectivity and rate of copper radioisotope complexation: formation and dissociation kinetic studies of 1,4,8-trimethylcyclam-based ligands with different coordinating pendant arms

PAÚROVÁ, Monika, Tomáš DAVID, Ivana CÍSAŘOVÁ, Přemysl LUBAL, Petr HERMANN et. al.

Basic information

Original name

Optimization of the selectivity and rate of copper radioisotope complexation: formation and dissociation kinetic studies of 1,4,8-trimethylcyclam-based ligands with different coordinating pendant arms

Authors

PAÚROVÁ, Monika (203 Czech Republic), Tomáš DAVID (203 Czech Republic), Ivana CÍSAŘOVÁ (203 Czech Republic), Přemysl LUBAL (203 Czech Republic), Petr HERMANN (203 Czech Republic, belonging to the institution) and Jan KOTEK (203 Czech Republic, guarantor, belonging to the institution)

Edition

New Journal of Chemistry, Cambridge, ROYAL SOC. CHEMISTRY, 2018, 1144-0546

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10402 Inorganic and nuclear chemistry

Country of publisher

United Kingdom of Great Britain and Northern Ireland

Confidentiality degree

není předmětem státního či obchodního tajemství

References:

Impact factor

Impact factor: 3.069

RIV identification code

RIV/00216224:14310/18:00103746

Organization unit

Faculty of Science

UT WoS

000438394800083

Keywords in English

ALKYLATED CYCLAM LIGANDS; METALCOMPLEXES; CYCLAM; MACROCYCLIC LIGANDS; CRYSTAL STRUCTURES; RADIOPHARMACEUTICALS

Tags

International impact, Reviewed
Změněno: 2/5/2019 15:06, Mgr. Tereza Miškechová

Abstract

V originále

Selectivity and rate of complex formation with metal radionuclides are crucial parameters for the utilization of ligating systems in nuclear medicine. One of the very suitable metals used in these applications is copper, which has a number of radioisotopes with useful properties. The thermodynamic and kinetic properties of Cu(ii) complexes with 10 macrocyclic 1,4,8-trimethylcyclam-based ligands having one coordinating acid pendant arm (Me(3)cyclam-R) were investigated in solution, allowing a direct comparison of the influence of the particular pendant arm on the properties of the complexes. They include the derivative with R = CH2CO2H (HL1) and a family containing various phosphorus acids R = CH2P(O)(OH)-X, where X = OEt (HL2); X = OH (H2L3); X = H (HL4); X = CH2CH2CO2H (H2L5); X = CH2P(O)(H)OH (H2L6); X = CH2P(O)(OH)(2) (H3L7); X = CH2N(CH2C6H5)(2) (HL8); X = CH2NH2 (HL9) and X = CH2N(CH2CO2H)(2) (H3L10). For comparison, 1,4,8,11-tetramethylcyclam (TMC: R = Me) was used. The formation kinetics showed that ligands endowed with a coordinating pendant arm bind Cu(ii) ions much faster when compared to TMC. At pH < 4, the fastest complexation was observed for acetate derivative HL1. At higher pH and, especially, at pH relevant for living and biocompatible systems (pH approximate to 6-7), the ligands with methylene(phosphonatomethyl)phosphinate and methylenephosphonate pendant arms (H3L7 and H2L3) showed the fastest complexation. Acid-assisted dissociation of Cu(ii) complexes with the ligands endowed with a coordinating pendant arm is similar for all studied systems ((1/2) = 7-35 min, 1 M HClO4, 25 degrees C). In contrast, the inertness of the Cu(ii)-TMC complex is much lower ((1/2) = 22 s under the same conditions). Potentiometric study of the selected ligands has confirmed a high thermodynamic selectivity of the studied ligands for Cu(ii) binding over complexation of Ni(ii) and Zn(ii) (the differences between the stability constants reach 6-7 orders of magnitude). Fast complexation of Cu(ii) at radio-level concentrations was observed, showing that the best ligands for potential in vivo use are those containing phosphonate or mixed geminal phosphinate-phosphonate pendant groups. One of the ligands (H2L3) and three Cu(ii) complexes (of H2L5, H3L7 and H3L10) were structurally characterized by means of X-ray diffraction study. The predicted conformation I of the macrocycle was confirmed in all three complexes.