Investigations on Organolanthanide Derivatives with the Hydrazonido (−NHN═CPh2) Ligand: Synthesis, Crystal Structure, and Reactivity

Abstract

Two organolanthanide complexes with the benzophenone hydrazonido(1−) ligand, [Cp2Yb(μ-NHN═CPh2)]2 (1) and Cp2Er[η2-NHN═CPh2](THF) (2), were synthesized by abstraction of cyclopentadienyl from Cp3Ln with 1 equiv of benzophenone hydrazone in THF. Reaction of 1 and 2 with phenyl isocyanate gives Ln−N bond insertion with the 1,3-H migration products Cp2Ln(η2-OC(NHPh)NN═CPh2)(HMPA) (Ln = Yb (3), Er (4)). However, 1 and 2 react with PhNCS to give Ln−N bond insertion without the 1,3-H migration products Cp2Ln(η2-SC(NHN═CPh2)NPh)(HMPA) (Ln = Yb (5), Er (6)) under the same conditions. PhCN inserts into the Er−N bond of 2 with 1,3-hydrogen migration to form the organolanthanide heterometallacycles Cp2Er[η2-NHC(Ph)NN═CPh2] (7). However, tBuNC does not insert into the Er−N bond of 2 under the same conditions, and treatment of 2 with tBuNC leads to the isolation of the solvent-free dimer [Cp2Er(μ-η1:η2-NHN═CPh2)]2 (2′). All new compounds have been characterized through X-ray single-crystal diffraction analysis.