Homoleptic Enantiopure Lanthanide Complexes: Synthesis, Structure, and Characterization

Herein, we report on a new class of enantiopure homoleptic lanthanide complexes stabilized by chiral iminophosphonamide ligands. The reaction of anhydrous lanthanide trichlorides with [KL]2 (L = [Ph2P{N(R)CH(CH3)Ph}2] = (R)-PEPIA)) in a 1:3 molar ratio yielded a series of homoleptic lanthanide complexes with the general formula of L3Ln (Ln = Y, La, Sm, Tb, and Lu). The X-ray structural determination revealed that the rare-earth metal ion is hexacoordinated by three iminophosphonamide ligands, and an enantiomeric pure propeller-type structure with a ?-configuration was observed for all complexes. The photoluminescence properties of the Sm(III) complex and the Tb(III) complex were studied. The Tb(III) complex showed ligand-absorption-enhanced, long-lived, metal-centered green photoluminescence with a quantum yield of 15% in the solid state.

Automated summary

We report the synthesis of a new class of enantiopure homoleptic lanthanide complexes utilizing chiral iminophosphonamide ligands. The complexes exhibit a propeller-type structure and the rare-earth metal ion is hexacoordinated by three iminophosphonamide ligands. Photoluminescence studies reveal long-lived, ligand-absorption-enhanced, metal-centered green emission with a quantum yield of 15% for the Tb(III) complex in the solid state.