Kinetic study of dissociation of a copper(II) complex of a 14-membered tetraaza-macrocyclic ligand containing pyridine and pendant N-carboxymethyl arms
| Autor: | Sylvie Blanc, Premysl Lubal, Rita Delgado, Anne-Marie Albrecht-Gary, Judite Costa |
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| Přispěvatelé: | Ecole Européenne de Chimie, Polymères et Matériaux de Strasbourg (ECPM - UNIVERSITÉ LOUIS PASTEUR), Université Louis Pasteur - Strasbourg I, Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Repositório da Universidade de Lisboa |
| Jazyk: | angličtina |
| Rok vydání: | 2008 |
| Předmět: |
Reaction mechanism
Stereochemistry Pyridinylbackbone Chemistry Multidisciplinary Kinetics chemistry.chemical_element Azacrown macrocycles 010402 general chemistry 01 natural sciences Dissociation (chemistry) law.invention chemistry.chemical_compound law [CHIM.ANAL]Chemical Sciences/Analytical chemistry Pyridine Electron paramagnetic resonance Stability constants Tetraaza-macrocyclic ligands 010405 organic chemistry Pendant acetate arms General Chemistry Copper 0104 chemical sciences Crystallography chemistry Copper(II) complexes Macrocyclic ligand Isomerization |
| Zdroj: | Collection of Czechoslovak Chemical Communications Collection of Czechoslovak Chemical Communications, Institute of Organic Chemistry & Biochemistry, 2008, 73 (2), pp.258--274. ⟨10.1135/cccc20080258⟩ Repositório Científico de Acesso Aberto de Portugal Repositório Científico de Acesso Aberto de Portugal (RCAAP) instacron:RCAAP |
| ISSN: | 0010-0765 1212-6950 |
| Popis: | The kinetics of acid-catalyzed dissociation of the copper(II) complex with 7-methyl-3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),13,15-triene-3,11-diacetic acid (ac2Me[14]pyN4) at [H+] = 0.05-0.25 mol l-1, I = 0.25 mol l-1 (Na, H)ClO4, and T = 298.16 K was studied with conventional and stopped-flow UV/VIS spectroscopy. Three steps of consecutive complex reaction were observed. The very fast first and second steps characterized by k1 = 70 ± 10 and k2 = 0.23 ± 0.01 l mol-1 s-1 depend on the H+ concentration. The third step is very slow, k3 = (1.08 ± 0.03) × 10-3 s-1, and does not depend on the H+ concentration. Latter rate-determining step involves an isomerisation process forcing the copper(II) ion to leave rapidly the macrocyclic cavity. The reaction mechanism of the complex dissociation has been proposed, taking into account the results obtained for related systems by independent methods: potentiometry, UV/VIS and EPR spectroscopies, X-ray diffraction analysis, and molecular mechanics calculations. |
| Databáze: | OpenAIRE |
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