Avens, LR; Barnhart, DM; Burns, CJ; Mckee, SD; Smith, WH
The oxidation chemistry of the uranium(III) aryloxide complex U(OAr)3 (OAr = 2,6-di-tert-butylphenoxide) has been explored with a variety of one-electron oxidants. Oxidation of U(OAr)3 with either AgBF4 or AgPF6 produces the uranium(IV) fluoride FU(OAr)3, 1. The analogous chloride compound, ClU(OAr)3, 2, is prepared by reaction with either benzyl chloride or PCl5. Oxidation by AgBr, CBr4, or PBr5 yields BrU(OAr)3, 3. Oxidation of U(OAr)3 by elemental iodine yields IU(OAr)3, 4. Compound 4 crystallizes in the space group P21/n, with unit cell dimensions a = 20.005(6) Ã
, b = 10.228(4) Ã
, c = 21.879(6) Ã
, β = 115.30(2)°, V = 4047(2) Ã
3 123, and Z = 4. Oxidation of U(OAr)3 with CI4 (carbon tetraiodide) does not yield 4 but rather gives rise to I2U(OAr)2, 5. Orthorhombic crystals of the THF adduct I2U(OAr)2(THF) were obtained from THF/hexane. I2U(OAr)2(THF) crystallizes in the space group Pbca, with unit cell dimensions a = 18.197(2) Ã
, b = 17.866(2) Ã
, c = 20.930(3) Ã
, V = 6804.5(14) Ã
3, and Z = 8. The chalcogenide-bridged compounds (ArO)3UâOâU(OAr)3, 6, and (ArO)3UâSâU(OAr)3, 7, can be prepared by reaction with a variety of chalcogen-donor reagents; reaction of the tris(aryloxido)- uranium complex with N2O, NO, Me3NO, or pyNO yields compound 6, while reaction with either COS or Ph3P=S affords 7. Compound 7 crystallizes as a diethyl ether solvate in the space group PI, with unit cell dimensions a = 13.290(3) Ã
, b = 13.744(4) Ã
, c = 14.643(5) Ã
, α = 81.41(2)°, β = 65.36(2)°, γ=67.58(2)°, V = 2247.4(11) Ã
3, and Z = 1. Oxidation of U(OAr)3 by molecular oxygen does not result in the isolation of the oxobridged dinuclear species but in the formation of the known uranium(IV) compound U(OAr)4 by ligand redistribution. © 1994, American Chemical Society. All rights reserved.