Terbocenium: completing a heavy lanthanide metallocenium cation family with an alternative anion abstraction strategy

A series of lanthanide metallocenium cations [Ln(Cp ttt ) 2 ] + (Ln = Y, Gd, Dy, Ho, Er, Tm, Yb, Lu; Cp ttt = C 5 H 2 t Bu 3 -1,2,4) were recently prepared, but curiously the Tb analogue was elusive. Here we access [Tb(Cp ttt ) 2 ] + via an alternative strategy, completing the heavy [Ln(Cp ttt ) 2 ] + family. A series of heavy lanthanide metallocenium cations [Ln(Cp ttt ) 2 ] + (Ln = Y, Gd, Dy, Ho, Er, Tm, Yb, Lu; Cp ttt = C 5 H 2 t Bu 3 -1,2,4) were recently prepared by halide abstraction of [Ln(Cp ttt ) 2 (Cl)], but curiously the Tb analogues remained elusive. Here we report an alternative anion abstraction strategy to access [Tb(Cp ttt ) 2 ] + completing the heavy [Ln(Cp ttt ) 2 ] + family.