Synthesis and characterization of heterobimetallic organo rare earth complexes bearing aryloxide-N-heterocyclic carbene ligands

Abstract

Two aryloxide-substituted N-heterocyclic carbene (NHC) proligands 3-[(2-hydroxynaphthalenyl) methyl]-1-mesityl-3,4,5,6- tetrahydropyrimidinium chloride (H2L1) and 3-(2-hydroxybenzyl)-1-mesityl-3,4,5,6-tetrahydropyrimidinium chloride (H2L2) were designed and easily synthesized via three synthetic processes in high yield. Four heterobimetallic potassium-NHC rare earth complexes L1KLnN″3 and L2KLnN″3 (L1, Ln = Y (1a), Nd (1b); L2, Ln = Y (2a), Nd (2b), N″ = N(SiMe3)2) were obtained by in-situ reaction of N-heterocyclic carbene proligands H2L1 and H2L2 with Ln[N(SiMe3)2]3 and KN(SiMe3)2 in toluene. The K-NHC rare earth complexes were characterized by single-crystal X-ray crystallography and Y complexes were characterized by 1H and 13C NMR spectroscopy. DFT calculations were employed to further investigate charge distributions and interactions within these compounds.