Unexpected C–H Bond Activation Promoted by Bimetallic Lanthanide Amido Complexes Bearing a META-Phenylene-Bridged Bis(β-diketiminate) Ligand

Abstract

Treatment of META-[Na(THF)2]2 (1; META = {[2,6-iPr2C6H3NC(Me)C(H)C(Me)N]−}2-(m-phenylene)] with 1 equiv of {Ln[N(SiMe3)2]2(μ-Cl)(THF)}2 (Ln = Y, Yb) in toluene at 110 °C afforded bimetallic lanthanide amido complexes bridged by a chloride and a phenyl group, {Ln[N(SiMe3)2]}2(META′)(μ-Cl) (Ln = Y (2), Yb (3)), which formed via unexpected C–H bond activation of the arene ring. However, the same reactions carried out in both THF and toluene at room temperature gave the bimetallic lanthanide amido–chloro complexes {Ln[N(SiMe3)2]2}META{Ln[N(SiMe3)2]Cl(THF)} (Ln = Y (4), Yb (5)). When they were heated to 110 °C in toluene, complexes 4 and 5 were converted to complexes 2 and 3 via amine elimination. All of these complexes were confirmed by elemental analysis, FT-IR, and X-ray structure analysis and by NMR analysis in the cases of complexes 1, 2, and 4.