Utilize este identificador para referenciar este registo:
https://hdl.handle.net/1822/74634
Título: | Complexes of bifunctional DO3A-N-(α-amino)propinate ligands with Mg(II), Ca(II), Cu(II), Zn(II), and lanthanide(III) ions: thermodynamic stability, formation and dissociation kinetics, and solution dynamic NMR studies |
Autor(es): | Garda, Zoltán Kócs, Tamara Bányai, István Martins, J. A. R. Kálmán, Ferenc Krisztián Tóth, Imre Geraldes, Carlos F. G. C. Tircsó, Gyula |
Palavras-chave: | Bifunctional ligands (BFCs) Complexes Equilibrium Formation and dissociation kinetics Dynamic NMR |
Data: | 16-Ago-2021 |
Editora: | Multidisciplinary Digital Publishing Institute (MDPI) |
Revista: | Molecules |
Citação: | Garda, Z.; Kócs, T.; Bányai, I.; Martins, J.A.; Kálmán, F.K.; Tóth, I.; Geraldes, C.F.G.C.; Tircsó, G. Complexes of Bifunctional DO3A-N-(α-amino)propinate Ligands with Mg(II), Ca(II), Cu(II), Zn(II), and Lanthanide(III) Ions: Thermodynamic Stability, Formation and Dissociation Kinetics, and Solution Dynamic NMR Studies. Molecules 2021, 26, 4956. https://doi.org/10.3390/molecules26164956 |
Resumo(s): | The thermodynamic, kinetic, and structural properties of Ln<sup>3+</sup> complexes with the bifunctional DO3A-ACE<sup>4−</sup> ligand and its amide derivative DO3A-BACE<sup>4−</sup> (modelling the case where DO3A-ACE<sup>4−</sup> ligand binds to vector molecules) have been studied in order to confirm the usefulness of the corresponding Gd<sup>3+</sup> complexes as relaxation labels of targeted MRI contrast agents. The stability constants of the Mg<sup>2+</sup> and Ca<sup>2+</sup> complexes of DO3A-ACE<sup>4−</sup> and DO3A-BACE<sup>4−</sup> complexes are lower than for DOTA<sup>4−</sup> and DO3A<sup>3−</sup>, while the Zn<sup>2+</sup> and Cu<sup>2+</sup> complexes have similar and higher stability than for DOTA<sup>4−</sup> and DO3A<sup>3−</sup> complexes. The stability constants of the Ln(DO3A-BACE)<sup>−</sup> complexes increase from Ce<sup>3+</sup> to Gd<sup>3+</sup> but remain practically constant for the late Ln<sup>3+</sup> ions (represented by Yb<sup>3+</sup>). The stability constants of the Ln(DO3A-ACE)<sup>4−</sup> and Ln(DO3A-BACE)<sup>4−</sup> complexes are several orders of magnitude lower than those of the corresponding DOTA<sup>4−</sup> and DO3A<sup>3−</sup> complexes. The formation rate of Eu(DO3A-ACE)<sup>−</sup> is one order of magnitude slower than for Eu(DOTA)<sup>−</sup>, due to the presence of the protonated amine group, which destabilizes the protonated intermediate complex. This protonated group causes the Ln(DO3A-ACE)<sup>−</sup> complexes to dissociate several orders of magnitude faster than Ln(DOTA)<sup>−</sup> and its absence in the Ln(DO3A-BACE)<sup>−</sup> complexes results in inertness similar to Ln(DOTA)<sup>−</sup> (as judged by the rate constants of acid assisted dissociation). The <sup>1</sup>H NMR spectra of the diamagnetic Y(DO3A-ACE)<sup>−</sup> and Y(DO3A-BACE)<sup>−</sup> reflect the slow dynamics at low temperatures of the intramolecular isomerization process between the SA pair of enantiomers, R-<i>Λ</i>(<i>λλλλ</i>) and S-<i>Δ</i>(<i>δδδδ</i>). The conformation of the C<sub>α</sub>-substituted pendant arm is different in the two complexes, where the bulky substituent is further away from the macrocyclic ring in Y(DO3A-BACE)<sup>−</sup> than the amino group in Y(DO3A-ACE)<sup>−</sup> to minimize steric hindrance. The temperature dependence of the spectra reflects slower ring motions than pendant arms rearrangements in both complexes. Although losing some thermodynamic stability relative to Gd(DOTA)<sup>−</sup>, Gd(DO3A-BACE)<sup>−</sup> is still quite inert, indicating the usefulness of the bifunctional DO3A-ACE<sup>4−</sup> in the design of GBCAs and Ln<sup>3+</sup>-based tags for protein structural NMR analysis. |
Tipo: | Artigo |
URI: | https://hdl.handle.net/1822/74634 |
DOI: | 10.3390/molecules26164956 |
ISSN: | 1420-3049 |
Versão da editora: | https://www.mdpi.com/1420-3049/26/16/4956 |
Arbitragem científica: | yes |
Acesso: | Acesso aberto |
Aparece nas coleções: |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
---|---|---|---|---|
molecules-26-04956-v2.pdf | 30,73 MB | Adobe PDF | Ver/Abrir |
Este trabalho está licenciado sob uma Licença Creative Commons