title: Control of oxo-group functionalization and reduction of the uranyl ion.
abstract: Uranyl complexes of a large, compartmental N8-macrocycle adopt a rigid, "Pacman" geometry that stabilizes the U(V) oxidation state and promotes chemistry at a single uranyl oxo-group. We present here new and straightforward routes to singly reduced and oxo-silylated uranyl Pacman complexes and propose mechanisms that account for the product formation, and the byproduct distributions that are formed using alternative reagents. Uranyl(VI) Pacman complexes in which one oxo-group is functionalized by a single metal cation are activated toward single-electron reduction. As such, the addition of a second equivalent of a Lewis acidic metal complex such as MgN″2 (N″ = N(SiMe3)2) forms a uranyl(V) complex in which both oxo-groups are Mg functionalized as a result of Mg-N bond homolysis. In contrast, reactions with the less Lewis acidic complex [Zn(N″)Cl] favor the formation of weaker U-O-Zn dative interactions, leading to reductive silylation of the uranyl oxo-group in preference to metalation. Spectroscopic, crystallographic, and computational analysis of these reactions and of oxo-metalated products isolated by other routes have allowed us to propose mechanisms that account for pathways to metalation or silylation of the exo-oxo-group.
authors: †EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, The King's Buildings, Edinburgh EH9 3FJ, U. K.
authors: Polly L
authors: PL
authors: Arnold
authors: †EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, The King's Buildings, Edinburgh EH9 3FJ, U. K.
authors: Anne-Frédérique
authors: AF
authors: Pécharman
authors: †EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, The King's Buildings, Edinburgh EH9 3FJ, U. K.
authors: Rianne M
authors: RM
authors: Lord
authors: †EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, The King's Buildings, Edinburgh EH9 3FJ, U. K.
authors: Guy M
authors: GM
authors: Jones
authors: †EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, The King's Buildings, Edinburgh EH9 3FJ, U. K.
authors: Emmalina
authors: E
authors: Hollis
authors: †EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, The King's Buildings, Edinburgh EH9 3FJ, U. K.
authors: Gary S
authors: GS
authors: Nichol
authors: ‡INSA, UPS, LPCNO, University of Toulouse, and CNRS, LPCNO UMR 5215, 135 Avenue de Rangueil, F-31077 Toulouse, France.
authors: Laurent
authors: L
authors: Maron
authors: ‡INSA, UPS, LPCNO, University of Toulouse, and CNRS, LPCNO UMR 5215, 135 Avenue de Rangueil, F-31077 Toulouse, France.
authors: Jian
authors: J
authors: Fang
authors: ‡INSA, UPS, LPCNO, University of Toulouse, and CNRS, LPCNO UMR 5215, 135 Avenue de Rangueil, F-31077 Toulouse, France.
authors: Thomas
authors: T
authors: Davin
authors: †EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, The King's Buildings, Edinburgh EH9 3FJ, U. K.
authors: Jason B
authors: JB
authors: Love
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D007477:Ions / Q000737:chemistry; D008958:Models, Molecular; D010084:Oxidation-Reduction; D012821:Silanes / Q000737:chemistry; D014501:Uranium / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D007477:Ions; D012821:Silanes; D014501:Uranium