Complexation of Mn(II) by Rigid Pyclen Diacetates: Equilibrium, Kinetic, Relaxometric, Density Functional Theory, and Superoxide Dismutase Activity Studies
| Autor: | Raphaël Tripier, Norbert Lihi, Gyula Tircsó, José L. Barriada, Nadège Hamon, Ferenc K. Kálmán, Enikő Molnár, Viktória Nagy, Balázs Váradi, Carlos Platas-Iglesias, Imre Tóth, David Esteban-Gómez, Zoltán Garda, Kristof Pota, Éva Tóth |
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| Přispěvatelé: | University of Debrecen Egyetem [Debrecen], Chimie, Electrochimie Moléculaires et Chimie Analytique (CEMCA), Institut Brestois Santé Agro Matière (IBSAM), Université de Brest (UBO)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Centro de Investigacións Científicas Avanzadas (CICA), Centre de biophysique moléculaire (CBM), Université d'Orléans (UO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université de Brest (UBO)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Brestois Santé Agro Matière (IBSAM), Université de Brest (UBO), Université d'Orléans (UO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), RENARD, NICOLAS |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Ethylenediaminetetraacetic acid
SOD activity Acetates 010402 general chemistry Ligands 01 natural sciences Medicinal chemistry Dissociation (chemistry) Oxalate Inorganic Chemistry Metal chemistry.chemical_compound Blood serum Coordination Complexes [CHIM] Chemical Sciences Humans [CHIM]Chemical Sciences [CHIM.COOR]Chemical Sciences/Coordination chemistry Physical and Theoretical Chemistry Density Functional Theory Manganese Molecular Structure 010405 organic chemistry Superoxide Ligand Superoxide Dismutase [CHIM.ORGA]Chemical Sciences/Organic chemistry Stereoisomerism [CHIM.COOR] Chemical Sciences/Coordination chemistry [CHIM.ORGA] Chemical Sciences/Organic chemistry 0104 chemical sciences Mn(II) complexes Kinetics chemistry visual_art Pyclen visual_art.visual_art_medium Chemical stability Relaxivity Azabicyclo Compounds MRI |
| Zdroj: | Inorganic Chemistry Inorganic Chemistry, American Chemical Society, 2021, ⟨10.1021/acs.inorgchem.0c03276⟩ Inorganic Chemistry, 2021, ⟨10.1021/acs.inorgchem.0c03276⟩ |
| ISSN: | 0020-1669 1520-510X |
| Popis: | International audience; We report the Mn(II) complexes with two pyclen-based ligands (pyclen = 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene) functionalized with acetate pendant arms at either positions 3,6 (3,6-PC2A) or 3,9 (3,9-PC2A) of the macrocyclic fragment. The 3,6-PC2A ligand was synthesized in five steps from pyclen oxalate by protecting one of the secondary amine groups of pyclen using Alloc protecting chemistry. The complex with 3,9-PC2A is characterized by a higher thermodynamic stability [log KMnL = 17.09(2)] than the 3,6-PC2A analogue [log KMnL = 15.53(1); 0.15 M NaCl]. Both complexes contain a water molecule coordinated to the metal ion, which results in relatively high 1H relaxivities (r1p = 2.72 and 2.91 mM–1 s–1 for the complexes with 3,6-PC2A and 3,9-PC2A, respectively, at 25 °C and 0.49 T). The coordinated water molecule displays fast exchange kinetics with the bulk in both cases; the rates (kex298) are 140 × 106 and 126 × 106 s–1 for [Mn(3,6-PC2A)(H2O)] and [Mn(3,9-PC2A)(H2O)], respectively. The two complexes were found to be remarkably inert with respect to their dissociation, with half-lives of 63 and 21 h, respectively, at pH = 7.4 in the presence of excess Cu(II). The r1p values recorded in blood serum remain constant at least over a period of 120 h. Cyclic voltammetry experiments show irreversible oxidation features shifted to higher potentials with respect to [Mn(EDTA)(H2O)]2– (H4EDTA = ethylenediaminetetraacetic acid) and [Mn(PhDTA)(H2O)]2– (H4PhDTA = phenylenediamine-N,N,N′,N′-tetraacetic acid), indicating that the PC2A complexes reported here have a lower tendency to stabilize Mn(III). The superoxide dismutase activity of the Mn(II) complexes was tested using the xanthine/xanthine oxidase/p-nitro blue tetrazolium chloride assay at pH = 7.8. The Mn(II) complexes of 3,6-PC2A and 3,9-PC2A are capable of assisting decomposition of the superoxide anion radical. The kinetic rate constant of the complex of 3,9-PC2A is smaller by 1 order of magnitude than that of 3,6-PC2A. |
| Databáze: | OpenAIRE |
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