Lanthanide Amide Complexes Supported by the Bis‐tris(pyrazolyl)borate Ligand Environment
The specific synthetic conditions to successfully access primary lanthanide amides in the bis-hydrotris(1-pyrazolyl)borate ligand environment [Ln(Tp)2(NHArCF3)] 3-Ln (Ln=Y, Dy; ArCF3=C6H3(CF3)2-3,5) are reported by either metathesis of [Ln(Tp)2(OTf)] 1-Ln (OTf=CF3SO3) with K(NHArCF3) or protonolysis of [Ln(Tp)2(N′′)] 2-Ln (N′′=N(SiMe3)2) with H2NArCF3 in toluene.
Abstract
Synthesis of primary lanthanide amides in the bis-hydrotris(1-pyrazolyl)borate ligand environment has been achieved. Salt metathesis of [Dy(Tp)2(OTf)] 1-Dy (OTf=CF3SO3) with K(N′′) (N′′=N(SiMe3)2) in toluene yielded the [bis(silyl)]amide [Dy(Tp)2(N′′)] 2-Dy. Complexes 1-Ln and 2-Ln were both used to access primary lanthanide amides, where either metathesis of 1-Ln with K(NHArCF3) (ArCF3=C6H3(CF3)2-3,5) or protonolysis of 2-Ln with H2NArCF3 in toluene yielded [Ln(Tp)2(NHArCF3)] 3-Ln (Ln=Y, Dy). The synthesis of parent amides was also attempted, but the metathesis of 1-Y with NaNH2 yielded complicated reaction mixtures, but from which the dimeric parent amide [{Y(Tp)2(μ-NH2)}2] 4-Y and an ‘ate’-salt [{Y(Tp)2(μ 2-OTf)(μ 3-OTf)Na(THF)2}2] 5-Y were isolated. Full characterisation data are presented for all complexes, including the structure determination.
