Selective coordination of Gallium(III), Zinc(II), and Copper(II) by an asymmetric dinucleating ligand

• Verfasst von: Bosch, Simone [VerfasserIn]
• Verfasst von: Comba, Peter [VerfasserIn]
• Verfasst von: Gahan, Lawrence R. [VerfasserIn]
• Verfasst von: Hanson, Graeme R. [VerfasserIn]
• Verfasst von: Noble, Christopher [VerfasserIn]
• Verfasst von: Schenk, Gerhard [VerfasserIn]
• Verfasst von: Wadepohl, Hubert [VerfasserIn]
• Titel: Selective coordination of Gallium(III), Zinc(II), and Copper(II) by an asymmetric dinucleating ligand
• Titelzusatz: a model for metallophosphatases
• Verf.angabe: Simone Bosch, Peter Comba, Lawrence R. Gahan, Graeme R. Hanson, Christopher Noble, Gerhard Schenk, and Hubert Wadepohl
• E-Jahr: 2015
• Jahr: 18 November 2015
• Umfang: 11 S.
• Fussnoten: Gesehen am 27.05.2020
• Titel Quelle: Enthalten in: Chemistry - a European journal
• Ort Quelle: Weinheim : Wiley-VCH, 1995
• Jahr Quelle: 2015
• Band/Heft Quelle: 21(2015), 50, Seite 18269-18279
• ISSN Quelle: 1521-3765
• DOI: doi:10.1002/chem.201503348
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: ligands
• Sach-SW: metalloenzymes
• Sach-SW: structure elucidation
• Sach-SW: transition metals
• Sach-SW: X-ray diffraction
• K10plus-PPN: 1698895631

Abstract

Abstract Complexation studies of the dinucleating ligand H3L (H3L=2-{[bis(pyridin-2-ylmethyl)amino]methyl}-6-{[bis(6-pivaloylamidopyridin-2-ylmethyl)amino]methyl}-4-methylphenol), with metal-binding sites?A and B, which both provide four donors to a metal ion; a tertiary amine; two pyridines (substituted with amide hydrogen-bond donors in site?B), and a bridging phenolate, with ZnII, CuII, and GaIII are reported. The titration of H3L with the three metal ions in solution was monitored by NMR spectroscopy or EPR and UV/Vis/near-IR spectroscopy, as well as by ESI-MS to analyze the selectivity of the two metal-ion sites?A and B of this model ligand for metallophosphatases; the spectroscopic assignments are supported by X-ray crystallography results. The first ZnII ion coordinates to site?A with unsubstituted pyridine donors and, upon addition of a second equivalent of ZnII, this coordinates to the sterically less accessible site?B. From a similar titration with GaIII, it emerges that only a mononuclear complex is obtained, with the GaIII center coordinated to site?A. When one equivalent of GaIII is reacted with the mononuclear ZnII complex, ZnII is forced by GaIII to exchange the site; this results in a dinuclear complex with GaIII in site?A and ZnII in site?B. With CuII, two isomers are observed: one with and the other without a bridging phenolate; these differ significantly in their spectroscopic and magnetic properties.