Tuning the Oxidation State, Nuclearity, and Chemistry of Uranium Hydrides with Phenylsilane and Temperature: The Case of the Classic Uranium(III) Hydride Complex [(C₅Me₅)₂U(μ-H)]₂

Abstract

This work demonstrates that the oxidation state and chemistry of uranium hydrides can be tuned with temperature and the stoichiometry of phenylsilane. The trivalent uranium hydride [(C 5 Me 5 ) 2 U−H] x (5) was found to be comprised of an equilibrium mixture of U(III) hydrides in solution at ambient temperature. A single U(III) species can be selectively prepared by treating (C 5 Me 5 ) 2 UMe 2 (4) with 2 equiv of phenylsilane at 50 °C. The U(III) system is a potent reducing agent and displayed chemistry distinct from the U(IV) system [(C 5 Me 5 ) 2 U(H)(μ-H)] 2 (2), which was harnessed to prepare a variety of organometallic complexes, including (C 5 Me 5 ) 2 U(dmpe)(H) (6), and the novel uranium(IV) metallacyclopentadiene complex (C 5 Me 5 ) 2 U(C 4 Me 4 ) (11).

Investigation of N‐Heterocyclic Carbene‐Supported Group 12 Triflates as Pre‐catalysts for Hydrosilylation/Borylation

“…Solvents were dried using aG rubbs-type solvent purification system [21] manufactured by Innovative Te chnologies, Inc.,d egassed (freeze-pump-thaw method), and stored under an atmosphere of nitrogen prior to use. 1 [23,24] For all DOSY experiments as pectral window of 6kHz was used with a3sa cquisition time and a2sS 4r elaxation delay with 8s cans for each gradient increment. AgOTf and HBPin were purchased from Matrix Scientific and used as received.…”

“…1 Ha nd 19 F{ 1 H} NMR revealed that no reaction had occurred. 1 Ha nd 19 F{ 1 H} NMR revealed that no reaction had occurred.…”

“…Crystals of the THF adduct, [IPr·Hg(OTf) 2 ·THF],s uitable for X-ray crystallographic analysis [15] were obtained by storing ac oncentrated solution of the product in THF layered with hexanes in a À35 8Cf reezer,o vernight; 1 The resulting mixture was stirred for 2hand filtered.…”

“…1 HNMR analysis in C 6 D 6 revealed that the reaction had proceeded to completion (TON = 21, TOF = 124 h À1 ). HBPin (28 mL, 0.19 mmol) was then immediately added to the reaction mixture.…”

“…[1] Of particulari nterest to this current study on Group 12 elementh ydrides, the parentb inaryM H 2 species( M = Zn, Cd and Hg) are reactive solids that have been known for over sixty years. [1] Of particulari nterest to this current study on Group 12 elementh ydrides, the parentb inaryM H 2 species( M = Zn, Cd and Hg) are reactive solids that have been known for over sixty years.…”