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NMR spectroscopy of a 18O-labeled rhodium paddlewheel complex: Isotope shifts, 103Rh–103Rh spin–spin coupling, and 103Rh singlet NMR.
- Source :
- Journal of Chemical Physics; 1/7/2024, Vol. 160 Issue 1, p1-11, 11p
- Publication Year :
- 2024
-
Abstract
- Despite the importance of rhodium complexes in catalysis, and the favorable 100% natural abundance of the spin-1/2 <superscript>103</superscript>Rh nucleus, there are few reports of <superscript>103</superscript>Rh nuclear magnetic resonance (NMR) parameters in the literature. In part, this is the consequence of the very low gyromagnetic ratio of <superscript>103</superscript>Rh and its dismal NMR sensitivity. In a previous paper [Harbor-Collins et al., J. Chem. Phys. 159, 104 307 (2023)], we demonstrated an NMR methodology for <superscript>1</superscript>H-enhanced <superscript>103</superscript>Rh NMR and demonstrated an application to the <superscript>103</superscript>Rh NMR of the dirhodium formate paddlewheel complex. In this paper, we employ selective <superscript>18</superscript>O labeling to break the magnetic equivalence of the <superscript>103</superscript>Rh spin pair of dirhodium formate. This allows the estimation of the <superscript>103</superscript>Rh–<superscript>103</superscript>Rh spin–spin coupling and provides access to the <superscript>103</superscript>Rh singlet state. We present the first measurement of a <superscript>18</superscript>O-induced <superscript>103</superscript>Rh secondary isotope shift as well as the first instance of singlet order generated in a <superscript>103</superscript>Rh spin pair. The field-dependence of <superscript>103</superscript>Rh singlet relaxation is measured by field-cycling NMR experiments. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00219606
- Volume :
- 160
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Journal of Chemical Physics
- Publication Type :
- Academic Journal
- Accession number :
- 174636826
- Full Text :
- https://doi.org/10.1063/5.0182233