Supramolecular control of a mononuclear biomimetic copper(II) center: bowl complexes vs funnel complexes.

Inorg Chem

Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques, Sorbonne Paris Cité, Université Paris Descartes, CNRS UMR 8601 , 45 Rue des Saints Pères, 75006 Paris, France.

Published: June 2014

Modeling the mononuclear site of copper enzymes is important for a better understanding of the factors controlling the reactivity of the metal center. A major difficulty stems from the difficult control of the nuclearity while maintaining free sites open to coordination of exogenous ligands. A supramolecular approach consists in associating a hydrophobic cavity to a tripodal ligand that will define the coordination spheres as well as access to the metal ion. Here, we describe the synthesis of a bowl Cu(II) complex based on the resorcinarene scaffold. This study supplements a previous work on Cu(I) coordination. It provides a complete picture of the cavity-copper system in its two oxidation states. The first XRD structure of such a bowl complex was obtained, evidencing a 5-coordinate Cu(II) ion with the three imidazole donors bound to the metal (two in the base of the pyramid, one in the apical position) and with an acetate anion, completing the base of the pyramid, and deeply included in the bowl. Solution studies conducted by EPR and UV-vis absorption spectroscopies as well as cyclic voltammetry highlighted interaction with coordinating solvents, various carboxylates that can sit either in the endo or in the exo position depending on their size as well as possible stabilization of hydroxo species in a mononuclear state. A comparison of the binding and redox properties of the bowl complex with funnel complexes based on the calix[6]arene core further highlights the importance of supramolecular features defining the first, second, and third coordination sphere for control of the metal ion.

Download full-text PDF

Source
http://dx.doi.org/10.1021/ic500740rDOI Listing

Publication Analysis

Top Keywords

funnel complexes
8
metal ion
8
bowl complex
8
base pyramid
8
bowl
5
supramolecular control
4
control mononuclear
4
mononuclear biomimetic
4
biomimetic copperii
4
copperii center
4

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!