title: Synthesis, Characterization, and Stoichiometric U-O Bond Scission in Uranyl Species Supported by Pyridine(diimine) Ligand Radicals.
abstract: Two uranium(VI) uranyl compounds, Cp*UO2((Mes)PDI(Me)) (3) and Cp*UO2((t)Bu-(Mes)PDI(Me)) (3-(t)Bu) (Cp* = 1,2,3,4,5-pentamethylcyclopentadienide; (Mes)PDI(Me) = 2,6-((Mes)N=CMe)2C5H3N; (t)Bu-(Mes)PDI(Me) = 2,6-((Mes)N=CMe)2-p-C(CH3)3C5H2N; Mes = 2,4,6-trimethylphenyl), have been synthesized by addition of N-methylmorpholine N-oxide to trianionic pyridine(diimine) uranium(IV) precursors, Cp*U((Mes)PDI(Me))(THF) (1), Cp*U((Mes)PDI(Me))(HMPA) (1-HMPA), and Cp*U((t)Bu-(Mes)PDI(Me))(THF) (1-(t)Bu). These uranyl complexes contain singly reduced pyridine(diimine) ligands suggesting formation occurs via cooperative ligand/metal oxidation. Treating 3 or 3-(t)Bu with stoichiometric equivalents of Me3SiI results in stepwise oxo silylation to form (Me3SiO)2UI2((Mes)PDI(Me)) (5) or (Me3SiO)UI2((t)Bu-(Mes)PDI(Me)) (5-(t)Bu), respectively. Additional equivalents result in full uranium-oxo bond scission and formation of UI4(1,4-dioxane)2 with extrusion of hexamethyldisiloxane. The uranium complexes have been characterized via multinuclear NMR, vibrational, and electronic absorption spectroscopies and, in some cases, X-ray crystallography.
authors: H.C. Brown Laboratory, Department of Chemistry, Purdue University , West Lafayette, Indiana 47906, United States.
authors: John J
authors: JJ
authors: Kiernicki
authors: H.C. Brown Laboratory, Department of Chemistry, Purdue University , West Lafayette, Indiana 47906, United States.
authors: Dennis P
authors: DP
authors: Cladis
authors: H.C. Brown Laboratory, Department of Chemistry, Purdue University , West Lafayette, Indiana 47906, United States.
authors: Phillip E
authors: PE
authors: Fanwick
authors: Department of Chemistry, Youngstown State University , Youngstown, Ohio 44555, United States.
authors: Matthias
authors: M
authors: Zeller
authors: H.C. Brown Laboratory, Department of Chemistry, Purdue University , West Lafayette, Indiana 47906, United States.
authors: Suzanne C
authors: SC
authors: Bart