Anion binding to a tetracopper resorcinarene-based complex |
| |
Authors: | Giuseppe Arena Raffaele P Bonomo Laura I Vagliasindi Valeria Zito John D Lamb |
| |
Institution: | 1. Department of Chemical Sciences , University of Catania , Viale A. Doria 6, 95125 , Catania , Italy garena@unict.it;3. Department of Chemical Sciences , University of Catania , Viale A. Doria 6, 95125 , Catania , Italy;4. CNR-Institute of Biostructure and Bioimaging Catania , Viale A. Doria 6, 95125 , Catania , Italy;5. Department of Chemistry and Biochemistry , Brigham Young University , Provo , UT , 84602 , USA |
| |
Abstract: | UV–vis and electron paramagnetic resonance (EPR) spectroscopic studies have been carried out on the multinuclear copper(II) complex Cu4BpaRes. The copper atoms are in a tetragonal distorted geometry with nitrogens from bispicolylamine (Bpa) coordinating in the equatorial plane and water molecules or anions completing four coordination sites. The interaction of anions with this polynuclear copper complex in aqueous solution supports the formation of different complex species, which depend on the type and the concentration of the anions. In the presence of excess anions, frozen solution EPR parameters show the formation of species in which the in-plane coordination is characterised by the presence of three nitrogen atoms coming from the ligand and a donor atom from the specific anion. For the bidentate anion ligands and especially for malonate, UV–vis titrations indicate the formation of a 1:4 (Cu4BpaRes:anion) species. EPR experiments support the formation of such a species and indicate that the four copper centres are equivalent and reach penta-coordination via the coordination of both oxygens from the bidentate ligand. |
| |
Keywords: | resorcinarene anion binding malonate |
|
|