Synthesis and characterization of bridged bis(amidato) rare earth metal amides and their applications in C-N bond formation reactions

Based on three bisamide pro ligands H2Ln (n = 1-3) (H2Ln = f(Me3C6H2CONHCH2)(2)CH2), H2L2 = l(Me3C6H2CONHCH2)(2)C(CH3)(2)], H2L3 = Ne3C H2CONH(CH2)(2)](2)NCH3), eight bis(amidato) trivalent rareearth metal amides {L'REIN(TMS)(2)](2) (n = 1, RE = La (1), Sm (2), Nd (3), Y (4); n = 2, RE = La (5), Nd (6); n = 3, RE = La (7), Nd (8); TMS = SiMe3) were successfully synthesized by treatment of FIX with RE[N(TMS),13 in a 1 :1 molar ratio. Complexes 3, and 5-8 were characterized by single -crystal X-ray diffraction, and NMR characterization was carried out for the La complexes 1, 5, 7 and the Y complex 4. These complexes exhibited high catalytic activities in both the direct amidation of aldehydes and the addition of amines with carbodiimine. It was found that the bis(amidato) rare earth metal amides bearing different linkers have different effects on the transformations and lanthanum and neodymium complexes performed better than others.