Nickel(II) and copper(II) Schiff base complexes bearing benzo-15-crown-5 functionalities as probes for spectroscopic recognition of lanthanide ions

• Type: Article in International Scientific Journal
• Date: 2004

Authors

Sousa, C (Author) Other; Gameiro, P (Author) FCUP; Freire, C (Author) FCUP; de Castro, B (Author) FCUP

Journal

Title: Polyhedron

Vol. 23

Pages: 1401-1408

ISSN: 0277-5387

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 50 Citations

Scopus - 53 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-000-ADP

DOI: 10.1016/j.poly.2004.02.014

Abstract (EN): A combination of host guest and coordination chemistry in the design of a spectroscopic sensor for lanthanide and aluminium ions is described. Nickel(II) and copper(II) complexes with a N2O Schiff base ligand and bearing two benzo-15-crown-5 moieties as flexible arms have been prepared and characterised by FAB-MS, UV-Vis and FTIR spectroscopies and, depending on the transition metal, by H-1 NMR or EPR. Recognition studies of alkaline, alkaline-earth, aluminium and lanthanide ions have been attempted in dmf by UV-Vis spectroscopy. Charge transfer and intraligand electronic bands of the Ni(II) and Cu(II) complexes show significant changes only in the presence of the M3+ ions used, lanthanides (Er3+, Gd3+ and Pr3+) and Al3+. Spectral changes induced by increasing M3+ concentrations have allowed the calculation of stability constants associated with the coordination of one trivalent ion in each crown ether moiety, corresponding to the formation of 1:2 adducts (metal complex :M3+), with values of log beta(21) in the range 8.2-9.5. No apparent correlation is perceptible between log beta(21) values and the transition metal, but a cavity effect was detected for each metal complex since log beta(21) values increased as lanthanide radii increased.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8