Xenon trioxide is a thermodynamically unstable and extremely shock-sensitive oxidant, which releases 406 kJ mol–1 of energy upon decomposition to Xe and O2. Two new phases of XeO3, β-XeO3 (R3), and γ-XeO3 (R3c), have now been obtained and characterized by single-crystal X-ray diffraction. It was previously shown that XeO3 reacts with F− and Cl− to form a variety of fluoro- and chloroxenate, salts whose crystal structures have also been obtained. The reaction of XeO3 with [N(C2H5)4]X (X = Cl, Br) yielded the stable chloro- and bromoxenate cage anions, [X3(XeO3)3]3− and [X4(XeO3)4]4−, the first examples of Xe–Br bonds to be isolated in macroscopic amounts. Xenon trioxide forms adducts with a variety of N- and O-bases. Its reactions with CH3CN, CH3CH2CN, and pyridine yielded O3XeNCR, O3Xe(NCR)2 (R = CH3 and CH2CH3), and XeO3(NC5H5)3. When HF was present in the reaction mixture, nitrogen was protonated to give [C5H5NH]4[HF2]2[F2(XeO3)2]. The reaction of XeO3 with N-bases in water at 0 °C in the absence of HF also provided Xe–N bonded adducts, e.g., hexamine.XeO3.H2O and 2,2’-bipyridine.XeO3. The latter adducts provide the first examples of Xe(VI) coordinated to sp2- and sp3-hybridized N-bases, water, and a bidentate ligand. The first examples of O-bases coordinated to XeO3 have also been synthesized and characterized which include adducts of phosphine oxide, {(C6H5)3PO}2XeO3, dimethylsulfoxide, {(CH3)2SO}3(XeO3)2, pyridine-N-oxide, (C5H5NO)3(XeO3)2, acetone, {(CH3)2CO}3XeO3, and the oxidatively resistant [OTeF5]– anion which was synthesized in CH3CN as the [N(CH3)4][F5TeOXeO3(CH3CN)2] salt. Unlike XeO3, many of the aforementioned adducts are not shock-sensitive.

Coordination chemistry of xenon(VI) trioxide

255th National Meeting (2018)

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