Combining NMR of dynamic and paramagnetic molecules

• Verfasst von: Roquette, Pascal [VerfasserIn]
• Verfasst von: Maronna, Astrid Christine [VerfasserIn]
• Verfasst von: Reinmuth, Matthias [VerfasserIn]
• Verfasst von: Kaifer, Elisabeth [VerfasserIn]
• Verfasst von: Enders, Markus [VerfasserIn]
• Verfasst von: Himmel, Hans-Jörg [VerfasserIn]
• Titel: Combining NMR of dynamic and paramagnetic molecules
• Titelzusatz: fluxional high-spin Nickel(II) complexes bearing bisguanidine ligands
• Verf.angabe: Pascal Roquette, Astrid Maronna, Matthias Reinmuth, Elisabeth Kaifer, Markus Enders, and Hans-Jörg Himmel
• E-Jahr: 2011
• Jahr: 26 January 2011
• Umfang: 14 S.
• Fussnoten: Gesehen am 20.09.2022
• Titel Quelle: Enthalten in: Inorganic chemistry
• Ort Quelle: Washington, DC : American Chemical Society, 1962
• Jahr Quelle: 2011
• Band/Heft Quelle: 50(2011), 5, Seite 1942-1955
• ISSN Quelle: 1520-510X
• DOI: doi:10.1021/ic102420x
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1816998982

Abstract

A detailed nuclear magnetic resonance (NMR) study was carried out on a series of paramagnetic, tetrahedrally coordinated nickel(II) dihalide complexes featuring chelating guanidine ligands. A complete assignment of the NMR signals for all complexes was achieved by sophisticated NMR experiments, including correlation spectra. The effects of halide exchange, as well as the variation in the guanidine−metal bite angles on the paramagnetic shifts, were assessed. The paramagnetic shift was derived with the aid of the diamagnetic NMR spectra of the analogous Zn complexes, which were synthesized for this purpose. The experimentally derived paramagnetic shift was then compared with the values obtained from quantum chemical (DFT) calculations. Furthermore, variable-temperature NMR studies were recorded for all complexes. It is demonstrated that NMR spectroscopy can be applied to evaluate the rate constants of fast fluxional processes within paramagnetic and catalytically active metal complexes.