Room temperature C–N bond cleavage of anionic guanidinate ligand in rare-earth metal complexes

Abstract

The dissociation of the anionic guanidinate ligand NC(NMe₂)₂ promoted by rare-earth metal complexes at room temperature is described. Treatment of CpLnCl₂(THF)₃ with two equiv. of Li[NC(NMe₂)₂] in THF at room temperature affords [Cp₂Ln(μ-η¹:η²-L₂)]₂ (Ln = Y; L = NC(NMe₂)NC(NMe₂)₂) and CpLn[NC(NMe₂)₂](μ-η¹:η²-L)₂LnCp₂ (Ln = Dy) in moderated yields, respectively. YCl₃ reacts with three equiv. of Li[NC(NMe₂)₂] under the same conditions to give a trinuclear yttrium guanidinate [(Me₂N)₂CN]₅Y₃[μ-NC(NMe₂)₂]₂(μ-η¹:η²-L)₂ in 63% yield. These reactions show that rare-earth metals can promote a C–N bond cleavage of the guanidine anion [NC(NMe₂)₂]⁻ at room temperature. All new complexes were characterized by elemental analysis and spectroscopic properties, and their solid-state structures were determined through single-crystal X-ray diffraction analysis.