Log in



C2TN

U…H-B AGOSTIC INTERACTIONS IN HOMOLEPTIC URANIUM(IV) BIS(MERCAPTOIMIDAZOLYL)BORATE COMPLEXES

G5 4

The choice of the ancillary ligand is crucial for the stabilization of metal complexes in various oxidation states and in promoting innovative reactivity. In a previous work in our lab, monoanionic hydrobis(mercaptoimidazolyl)borate ligands showed their ability to stabilize trivalent uranium complexes. Studies were pursued in order to access complexes with uranium in other oxidation states. Oxidation reactions of the trivalent uranium complex [UI(k3-{H(Ph)B(timMe)2})2] provided access to the new homoleptic cationic uranium(IV) complexes [U(k3-{H(Ph)B(timMe)2})3][X] (X = BPh4, I; timMe = 2-mercapto-1-methylimidazolyl). Multinuclear NMR and IR spectroscopies and X-ray diffraction analysis were consistent with a k3-H,S,S coordination mode for the three hydrobis(mercaptoimidazolyl)borate ligands, favoring nine-coordinated U(IV) complexes in tricapped trigonal prismatic geometries. These recent results expand the field of non-aqueous uranium chemistry with soft donor ligands and demonstrate that hydrobis(mercaptoimidazolyl)borate ligands can also form robust complexes with U4+ ions.