Uranium(IV) Halide (F-, Cl-, Br-, and I-) Monoarene Complexes

The syntheses of four nearly isostructural uranium(IV) monoarene complexes, supported by the arene anchored tris- (aryloxide) chelate, [((ArO)-Ar-Ad,Me)(3)mes](3-), are reported. Oxidation of the uranium(III) precursor [(((ArO)-Ar-Ad,Me)(3)mes)U], 1, in the presence of tetrahydrofuran (THF) results in THF coordination and distortion of the equatorial coordination sphere to afford the uranium(IV) eta(6)-arene, complexes, [(((Ad,Me)Aro)(3)mes)U(X)(THF)], 2-X-THF, (where X = F, Cl, Br, or I) as their THF adducts. The solvate-free trigonally ligated [(((Ad,Me)Aro)(3)mes)U(F)], 2-F, was prepared and isolated in the absence of coordinating solvents for comparison.