Replacement of Trimethylamine in Trimethylamine-trispentafluoroethyl-borane. Structures of [(C2F5)3BNMe3], [NMe4][(C2F5)3BOH], and K[(C2F5)3BCH2(CO)C6H5]

Trimethylamine‐tris(pentafluoroethyl)borane [(C2F5)3BNMe3] (1) reacts at 190 °C with water under displacement of the trimethylamine ligand to yield the hydroxy‐tris(pentafluoroethyl)borate [(C2F5)3BOH]− (2). In tributylamine 1 reacts with alkynes HC≡CR to form novel ethynyl‐tris(pentafluoroethyl)borate anions [(C2F5)3BC≡CR]− – R = C6H5 (3), C6H4CH3 (4), Si(CH(CH3)2)3 (5) – in moderate yields. Compound 3 adds water across the triple bond to form the novel anion [(C2F5)3BCH2(CO)C6H5]− (6). The structures of [(C2F5)3BNMe3], [NMe4][(C2F5)3BOH] and K[(C2F5)3BCH2(CO)C6H5] have been determined by x‐ray crystallography.