Synthesis and reactivity of bis-tris(pyrazolyl)borate lanthanide-aluminium heterobimetallic trihydride complexes

Molecular heterobimetallic hydride complexes of lanthanides (Ln) and main group (MG) metals exhibit chemical properties unique from their monometallic counterparts and are highly reactive species, making their synthesis and isolation challenging. Herein, molecular Ln/Al heterobimetallic trihydrides [Ln(Tp)2(-H)2Al(H)(Nʹʹ)] 2-Ln (Ln = Y, Sm, Dy, Yb; Tp = hydrotris(1-pyrazolyl)borate; Nʹʹ = N(SiMe3)2) have been synthesised by facile insertion of aminoalane [Me3N•AlH3] into the Ln–N amide bonds of [Ln(Tp)2(Nʹʹ)] 1-Ln. Thus, providing a simple synthetic strategy to access a range of Ln/Al hydrides. Reactivity studies demonstrate that 2-Ln is a heterobimetallic hydride, for example it is able to reduce unsaturated substrates. Further evidence for the cooperative nature of 2-Ln is shown, as 2-Ln can catalytically dehydrocouple amine-borane under ambient conditions in contrast to its monomeric counterparts.