Solution Spectroscopic Analysis of Ligand Exchange in Uranium Mono-Oxo Complexes
Florian Ressnik1, Tyler-Rayne Nero1, Maximilian G Bernbeck1
1School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, Georgia30332, United States.
Abstract:
Four uranium mono-oxo imidophosphorane complexes with a closed set of systematically changed substituents (pyrrolidine vs piperidine and introduction of one tert-butyl group) are presented. All complexes exhibit an inverse trans-influence (ITI). The rapid exchange of axial and equatorial ligands at room temperature, the unique 31P nuclear magnetic resonance (NMR) handle of the ligands, and the complexes' overall closed-shell singlet ground state facilitate the determination of ligand-exchange barriers via variable-temperature (VT) and exchange spectroscopy (EXSY) NMR. Computational analysis delineates electronic and steric contributions to the experimentally determined exchange barriers.
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