Superacids Based on Pentafluoroorthotellurate Derivatives of Aluminum

The new Lewis acid Al(OTeF₅)₃ and its acetonitrile adduct CH₃CN→Al(OTeF₅)₃ were obtained by a simple one-step synthesis in batches of up to 15 g. Al(OTeF₅)₃ and the adduct were characterized by vibrational spectroscopy (IR, Raman) and quantum-chemical calculations. Furthermore, five different salts of the new weakly coordinating anion Al(OTeF₅)₄]⁻ were prepared in a two-step procedure. Ph₄P]Al(OTeF₅)₄], CsAl(OTeF₅)₄], Ph₃C]Al(OTeF₅)₄], as well as the protonated benzene derivatives C₉H₁₃]Al(OTeF₅)₄] and C₆H₇]Al(OTeF₅)₄] were characterized by low-temperature single-crystal X-ray diffraction and NMR spectroscopy. Arenium salts have rarely been characterized in the solid state and were synthesized in this work in a simplified fashion.