Synthesis and structural characterization of amine-bridged bis(phenolate) lanthanide complexes

Abstract

Lanthanide complexes supported by the tetradentate amine-bridged bis(phenolate) ligand LH2 [L = Me2NCH2CH2N{CH2-(2-O–C6H2–Bu2t-3,5)}2] were synthesized and structurally characterized. The reaction of (tBuCp)2NdCl(THF)2 with ligand LH2 in a 1:1 M ratio in THF at room temperature gave the amine-bridged bis(phenolate) lanthanide chloride LNdCl(DME) 1, (DME = 1,2-dimethoxyethane) in high yield. Complex 1 reacted with potassium amide to give the corresponding neodymium amido product LNdNPh2(DME) (2) in good yield. The ligand LH2 was subsequently treated with Cp3Ln to produce the amine-bridged bis(phenolato) cyclopentadienyl lanthanide complexes LLnCp(THF) (Ln = Yb (3) and Nd(4)). The definitive solid state molecular structure of complexes 1 and 3 were confirmed by single-crystal X-ray analysis. In complex 1 the central Nd atom is seven-coordinated with the coordination sphere completed by two oxygen atoms and two nitrogen atoms of the amine-bridged bis(phenolate) ligand, two oxygen atoms of DME molecule and one chlorine atom in a distorted capped octahedron while in complex 3 the Yb atom is six-coordinated by two oxygen atoms and two nitrogen atoms from the ligand, one oxygen atom from the coordinated THF molecule and a cyclopentadienyl group in a distorted octahedron.