Asymmetric zinc(ii) complexes as functional and structural models for phosphoesterases?

DALTON TRANSACTIONSDALTON T Pub Date: DOI: 10.1039/C3DT50514F

Abstract

We report two asymmetric ligands for the generation of structural and functional dinuclear metal complexes as phosphoesterase mimics. Two zinc(II) complexes, [Zn2(CH3L4)(CH3CO2)2]+ (CH3HL4 = 2-(((2-methoxyethyl)(pyridin-2-ylmethyl)amino)methyl)-4-methyl-6-(((pyridin-2-ylmethyl)amino)methyl)phenol) and [Zn2(CH3L5)(CH3CO2)2]+ (CH3HL5 = 2-(((2-methoxyethyl)(pyridine-2-ylmethyl)amino)methyl)-4-methyl-6-(((pyridin-2-ylmethyl)(4-vinylbenzyl)amino)methyl)phenol) were synthesized and characterized by X-ray crystallography. The structures showed that the ligands enforce a mixed 6,5-coordinate environment in the solid state. 1H-, 13C- and 31P-NMR, mass spectrometry and infrared spectroscopy were used to further characterize the compounds in the solid state and in solution. The zinc(II) complexes hydrolyzed the organophosphate substrate bis-(2,4-dinitrophenol)phosphate (BDNPP), the nucleophile proposed to be a terminal water molecule (pKa 7.2). The ligand CH3HL4 was immobilised on Merrifield resin and its zinc(II) complex generated. Infrared spectroscopy, microanalysis and XPS measurements confirmed successful immobilisation, with a catalyst loading of ～1.45 mmol g?1 resin. The resin bound complex was active towards BDNPP and displayed similar pH dependence to the complex in solution.

Graphical abstract: Asymmetric zinc(ii) complexes as functional and structural models for phosphoesterases
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