Single, double and triple deprotonation of a β-diketimine bearing pendant pyridyl group and the corresponding rare-earth metal complexes

A new beta-diketimine bearing the pendant pyridyl group, CH(3)C(2,6-((i)Pr)(2)C(6)H(3)NH)CHC(CH(3))(NCH(2)-C(5)NH(4)) (L1), was synthesized. The reaction of L1 with one equivalent of Sc(CH(2)SiMe(3))(3)(THF)(2) at room temperature gave a singly deprotonated product (L1-H)Sc(CH(2)SiMe(3))(2) (1). Y(CH(2)SiMe(3))(3)(THF)(2) under the same conditions led to the unexpected dimer [(L1-H(3))Y(THF)](2) (2), in which the ligand precursor L1 was triply deprotonated. The reaction of L1 with Y(CH(2)SiMe(3))(3)(THF)(2) at -35 degrees C provided a mixture of singly deprotonated product (L1-H)Y(CH(2)SiMe(3))(2) (3) and doubly deprotonated product (L1-H(2))Y(CH(2)SiMe(3))(THF)(2) (4). The reactions of L1 with Ln[N(SiMe(3))(2)](3) gave only singly deprotonated products (L1-H)Ln[N(SiMe(3))(2)](2) (5: Ln = Y; 6: Ln = La). The complexes 1, 2 and 4-6 have been characterized by single-crystal X-ray diffraction.