Reactivity of UI₄(OEt₂)₂ with phenols: probing the chemistry of the U–I bond

Solutions of UI₄(OEt₂)₂ in Et₂O were found to deposit orange crystals of [H(OEt₂)₂][UI₅(OEt₂)] (1) upon standing at room temperature. The proton in the cation of 1 most likely originates from the surface of the glass vial in which the solution was stored. Reactions of UI₄(OEt₂)₂ with 1 equiv. of ArOH in toluene, followed by addition of THF, provides UI₃(OAr)(THF)_x (Ar = Ph, x = 3, 2; Ar = 2,6-Ph₂C₆H₃, x = 2, 3). UI₄(OEt₂)₂ also reacts with 2 equiv. of ArOH (Ar = Ph, 4-^tBuC₆H₄, 2,6-Me₂C₆H₃, C₆F₅) in toluene, followed by addition of THF, to generate UI₂(OC₆H₅)₂(THF)₃ (4), UI₂(O-4-^tBuC₆H₄)₂(THF)₃ (5), UI₂(O-2,6-Me₂C₆H₃)₂(THF)₃ (6) and UI₂(OC₆F₅)₂(THF)₃ (7), in moderate yields. Complete conversion to the products requires the use of a dynamic vacuum to remove the HI generated upon addition of the phenol.