Probing Homogeneous Catalysts and Precatalysts in Solution by Exchange-Mediated Overhauser Dynamic Nuclear Polarization NMR
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Date
2024-05-08Type
- Journal Article
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Abstract
Triphenylphosphine (PPh₃) is a ubiquitous ligand in organometallic chemistry that has been shown to give enhanced ³¹P NMR signals at high magnetic field via a scalar-dominated Overhauser effect dynamic nuclear polarization (OE DNP). However, PPh₃ can only be polarized via DNP in the free form, while the coordinated form is DNP-inactive. Here, we demonstrate the possibility of enhancing the ³¹P NMR signals of coordinated PPh3 in metal complexes in solution at room temperature by combining Overhauser effect DNP and chemical exchange between the free and coordinated PPh₃ forms. With this method, we successfully obtain ³¹P DNP enhancements of up to 2 orders of magnitude for the PPh₃ ligands in Rh(I), Ru(II), Pd(II), and Pt(II) complexes, and we show that the DNP enhancements can be used to determine the activation energy of the ligand exchange reaction. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000676440Publication status
publishedExternal links
Journal / series
Journal of the American Chemical SocietyVolume
Pages / Article No.
Publisher
American Chemical SocietySubject
Electromagnetic radiation; Ligands; Metals; Nuclear magnetic resonance spectroscopy; PolarizationMore
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