Publication details
KINETIC AND MECHANISTIC STUDY OF DISSOCIATION OF COPPER(II) COMPLEX WITH 14-MEMBERED TETRAAZAMACROCYCLE LIGAND CONTAINING PYRIDINE AND N-CARBOXYMETHYL ARMS
| Authors | |
|---|---|
| Year of publication | 2008 |
| Type | Article in Periodical |
| Magazine / Source | Collection of Czechoslovak Chemical Communications |
| MU Faculty or unit | |
| Citation | |
| Field | Inorganic chemistry |
| Keywords | Copper(II) complexes; Pendant acetate arms; Tetraaza-macrocyclic ligands; Aza-crown macrocycles; Pyridinylbackbone |
| Description | 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 M, I = 0.25 M (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 M-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. |