Facile Synthesis of Organolanthanide Hydrides with Metallic Potassium: Crystal Structures and Reactivity

A “new” strategy for the preparation of organolanthanide neutral hydrides by the reaction of organolanthanide chlorides with metallic potassium and their reactivity toward isocyanide has been studied. Treatment of [Me2Si(C5H4)2LnCl]2 with excess metallic potassium in THF results in a direct chlorine-abstracted reaction to yield the corresponding organolanthanide hydrides {μ-[η5-Me2Si(C5H4)2Ln]}2(μ-H)2 (Ln = Y (1), Er (2), Gd (3)) in moderate yields. Structural determination results indicated that complex 1 is a solvated neutral dimer with two bridging hydrogen atoms. Further investigations on their reactivity display that tert-butyl isocyanide (CNtBu) readily inserts into the Ln–H bonds of 1–3 to form lanthanocene N-alkylformimidoyl complexes {μ-[η5-Me2Si(C5H4)2Ln]}2(μ,η2-HCNCMe3)2 (Ln = Y (4), Er (5), Gd (6)). All compounds were characterized by elemental analysis and spectroscopic properties. The solid-state structures of complexes 1 and 4–6 were determined through X-ray single-crystal diffraction analysis.