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Abstract Bond distance is a common structural metric used to assess changes in metal–ligand bonds, but it is not clear how sensitive changes in bond distances are with respect to changes in metal–ligand covalency. Here we report ligand K‐edge XAS studies on Ni and Pd complexes containing different phosphorus(III) ligands. Despite the large number of electronic and structural permutations, P K‐edge pre‐edge peak intensities reveal a remarkable correlation that spectroscopically quantifies the linear interdependence of covalent M−P σ bonding and bond distance. Cl K‐edge studies conducted on many of the same Ni and Pd compounds revealed a poor correlation between M−Cl bond distance and covalency, but a strong correlation was established by analyzing Cl K‐edge data for Ti complexes with a wider range of Ti−Cl bond distances. Together these results establish a quantitative framework to begin making more accurate assessments of metal–ligand covalency using bond distances from readily‐available crystallographic data.
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Quantifying the Influence of Covalent Metal‐Ligand Bonding on Differing Reactivity of Trivalent Uranium and Lanthanide Complexes
Abstract Qualitative differences in the reactivity of trivalent lanthanide and actinide complexes have long been attributed to differences in covalent metal‐ligand bonding, but there are few examples where thermodynamic aspects of this relationship have been quantified, especially with U3+and in the absence of competing variables. Here we report a series of dimeric phosphinodiboranate complexes with trivalentf‐metals that show how shorter‐than‐expected U−B distances indicative of increased covalency give rise to measurable differences in solution deoligomerization reactivity when compared to isostructural complexes with similarly sized lanthanides. These results, which are in excellent agreement with supporting DFT and QTAIM calculations, afford rare experimental evidence concerning the measured effect of variations in metal‐ligand covalency on the reactivity of trivalent uranium and lanthanide complexes.
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- Award ID(s):
- 2017828
- PAR ID:
- 10373511
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 61
- Issue:
- 45
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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