Facile synthesis and characterization of neutral carbon-bridged bis(phenolate) lanthanide derivatives

The reactions of (C5H5)3Ln(THF) with 2,2′-ethylene-bis(4,6-di-tert-butylphenol) (EDBPH2) in a 1:1 molar ratio in THF gave the cyclopentadienyl bis(phenolate) lanthanide complexes (C5H5)Ln(EDBP)(THF)2 (Ln = Yb (1), Sm (2), Nd (3)) in nearly quantitative yields. The coordinated THF can be readily replaced by DME to give (C5H5)Ln(EDBP)(DME) (Ln = Yb (1a), Sm (2a)). Complexes 1 to 3 further reacted with 1 equivalent of isopropanol in THF to yield the neutral bis(phenolate) lanthanide isopropoxide [(EDBP)2Ln(μ-OPri)(THF)2]2 (Ln = Yb (4), Sm (5), Nd (6)) in high yields. The definitive molecular structures of complexes 1a, 5 and 6 were determined by X-ray diffraction analysis.