Anion-selective receptors based on dinuclear copper(II) and nickel(II) cage complexes of bis-salicylaldimines

• Published in: Journal of Inclusion Phenomena and Macrocyclic Chemistry 2011-12, Vol.71 (3-4), p.529-536
• Main Authors: Chang, John Yu-Chih, Parsons, Simon, Plieger, Paul G., Tasker, Peter A.
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Crystallography and Scattering Methods; Food Science; Organic Chemistry; Original Article
• ISSN: 0923-0750; 1573-1111
• DOI: 10.1007/s10847-011-0011-x

The selectivity, anion uptake and exchangeability of anion-binding by metal salt extractants of the form [M 2 L 2 ] 4+ have been assessed by the method of anion exchange chromatography in biphasic systems. The order of sulfate-, nitrate-, and chloride-uptake into the solid copper(II) complex as of the dioxime pro-ligand N , N ′-dimethyl- N , N ′-hexamethylenedi(3-hydroxyiminomethyl-2-hydroxy-5- tert -butylbenzylamine ( L 1 ) is 56, 42, and 16%, respectively, consistent with the relative magnitudes of formation constants for the inclusion complexes, [A⊂Cu 2 L 1 2 ] n + where A = anion, found in UV–vis titration studies in a single phase. X-ray structural determination of the bis-benzylimine pro-ligand, N , N ′-dimethyl- N , N ′-hexamethylenedi-(3-benzyliminomehyl-2-hydroxy-5- tert -butylbenzylamine), nickel(II) sulfato complex [SO 4 ⊂Ni 2 L 2 2 ]SO 4 reveals the nickel atoms to have a significant tetrahedral distortion, providing more favourable sulfate-alkylammonium interactions within the cage.