Synthesis, characterization and catalytic activity of rare-earth metal amides incorporating cyclohexyl bridged bis(beta-diketiminato) ligands

摘要

A series of organo rare-earth metal amides incorporating chiral cyclohexyl bridged bis(beta-diketiminato) ligands with general formula LREN(SiMe3)(2) (L-1 = (1S, 2S)-1,2-Cy[NC(Me) CHC(Me) NAr](2), Ar = 2, 6-Et2C6H3, RE = Nd (1a), Dy (1b), Yb (1c), Y (1d); L-2 = (1R,2R)-1,2-Cy[NC(Me) CHC(Me) NAr](2), Ar = 2, 6-i-Pr2C6H3, RE = Nd (2a), Gd (2b), Dy (2c), Er (2d), Y (2e)) were synthesized in good yields via reactions of [(Me3Si)(2)N](3)REIII(m-Cl) Li(THF)(3) with H2L1 and H2L2. All compounds were fully characterized by spectroscopic methods and elemental analyses. The complexes 1d and 2e were also characterized by H-1 NMR and C-13 NMR spectral analyses. The structures of complexes 1a-d were determined by singlecrystal X-ray analyses. Investigation of the catalytic properties of the complexes indicated that all complexes exhibited a high catalytic activity towards the addition of diphenylphosphine oxide to b-nitroalkene and alpha, beta-unsaturated carbonyl derivatives with an excellent regioselectivity.