Structure and potential applications of amido lanthanide complexes chelated by bifunctional β-diketiminate ligand

The synthesis and structure of lanthanide(III) amides containing one bifunctional β-diketiminate ligand is reported. Compounds were obtained via a protolytic reaction of the free β-diketimine {N-[(2-MeO)C6H5]}NC(Me)CHC(Me)N(H){N′-[(2-MeO)C6H5]} (LCOH) or {N-[(2-MeO)C6H5]}NCHCHCHN(H){N′-[(2-MeO)C6H5]} (LHOH) with corresponding tris(amide) of the Ln[N(SiMe3)2]3 (Ln = Y, La, Nd, Sm, Eu, Gd and Yb) type in equimolar ratio at ambient temperature. Products were characterized by IR and/or multinuclear NMR spectroscopy techniques and structures of four of them have been determined by X-ray diffraction techniques. Complexes LCOY[N(SiMe3)2]2, LCOLa[N(SiMe3)2]2, LCONd[N(SiMe3)2]2 and LHOYb[N(SiMe3)2]2 crystalize as monomers with the six-coordinated metal centre by two amido and one tetradentate β-diketiminato ligands. Minor hydrolytic products of composition [LCOSmN(SiMe3)2]2O and (LCO)4O2(OH)4La4 were obtained and their structures contain two or four lanthanide atoms linked through the oxo- or hydroxo bridges. Diamagnetic complexes were tested for its potential applications in hydroamination and polymerization reactions, respectively, giving low conversion in all reactions.