Uranium triflate complexes.

Uranium triflate complexes. We review here the different preparations of uranium triflates that we have developed in the course of these last years in our laboratory. Protonation of [U]-R and [U]-NR2 (R = alkyl) bonds with pyridinium triflate constitutes a general and efficient route towards triflate complexes. This method is very suitable for the preparation of organometallic compounds such as U(Cp)(3)(OTf), U(Cp)(2)(OTf)(2)(py), U(Cp*)(2)(OTf)(2), and U(Cot)(OTf)(2)(py), which have been crystallographically characterised. The homoleptic species U(OTf)(n) (n = 3, 4) are easily prepared by heating a mixture of uranium turnings or UH3 in triflic acid. By adjusting the temperature to 120 or 180 degreesC, either U(OTf)(3) or U(OTf)(4) is isolated. Treatment of UO3 with pure or aqueous solution of triflic acid leads to the non-solvated uranyl triflate UO2(OTf)(2), which is more conveniently obtained by heating a suspension of UO3 in triflic anhydride. This reactant is an excellent dehydrating agent and enables the preparation of UO2(OTf)(2) and Ce (OTf)(4) from the hydrated starting materials.