[Se(CH₂C(O)CH₃)₃][B₁₂F₁₁NH₃]: The first selenium cation with three β-ketone substituents

Abstract

The reaction of [Se8][B12F11NH3]2 with acetone and subsequent crystallization from acetone/diethyl ether yielded the selenium cation [Se(CH2C(O)CH3)3]+ as a by-product, which is stabilized by the weakly coordinating undecafluorinated anion [B12F11NH3]−. While attempting to crystallize pure [Se8][B12F11NH3]2, the structure of the isolated product, namely, tris(2-oxopropyl)selenium 1-ammonioundecafluorododecaborate, was surprising. The cation [Se(CH2C(O)CH3)3]+ represents the first example for a cationic selenium compound with three ketone functional groups located in the β-position with respect to the selenium atom. The cation possesses almost trigonal–pyramidal C 3 symmetry and forms hydrogen bonds to the ammonio group of the anion.