title: Asymmetric zinc(II) complexes as functional and structural models for phosphoesterases.
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. (1)H-, (13)C- and (31)P-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 (pK(a) 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.
authors.affiliation: School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia.
authors.forename: Lena J
authors.initials: LJ
authors.lastname: Daumann
authors.forename: Laurène
authors.initials: L
authors.lastname: Marty
authors.forename: Gerhard
authors.initials: G
authors.lastname: Schenk
authors.forename: Lawrence R
authors.initials: LR
authors.lastname: Gahan
mesh_terms: D018360:Crystallography, X-Ray; D004950:Esterases / Q000737:chemistry* / Q000378:metabolism; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: D008024:Ligands; D009942:Organometallic Compounds; D004950:Esterases; D015032:Zinc