Syntheses of Dianionic α-Iminopyridine Rare-Earth Metal Complexes and Their Catalytic Acitivities toward Dehydrogenative Coupling of Amines with Hydrosilanes

Reactions of [(Me3Si)(2)N](3)RE(mu-Cl)Li(THF)(3) with aminomethylene-substituted pyridine 2-[O-(CH2CH2)(2)NCH2CH2NCH2]C5H4N (1) gave the dianionic alpha-iminopyridine rare-earth metal amido complexes {mu-eta(2):sigma(1):kappa(1):kappa(1)-2-[O(CH2CH2)(2)NCH2CH2NCH]C5H4N}(2)RE2[N(SiMe3)(2)](2) (RE = Y(2a), La(2b), Pr(2c), Nd(2d), Sm(2e), Dy(2f), Er(2g), and Lu (2h)). However, reaction of [(Me3Si)(2)N](3)Y(mu-CI)Li(THF)(3) with pyridin-2-ylmethyl-substituted amines such as 2-(RNHCH2)C5H4N (R = Bu-t (3a) and 2,6-(Pr2Ph)-Pr-i (3b)) or benzyl-substituted amine O(CH2CH2)(2)NCH2CH2NHCH2C6H5 (5) afforded the corresponding yttrium complexes containing monoanionic ligands [2-(RNCH2)C5H4N](2)YN(SiMe3)(2) (R = Bu-t (4a) and 2,6-(Pr2Ph)-Pr-i (4b)) or [O(CH2CH2)(2)NCH2CH2NCH2C6H5][(Me3Si)(2)N)]Y(gamma-Cl)(mu-eta(3)-O(CH2CH2)(2)NCH2CH2NCH2C6H5)-Li(THF) (6). Dianionic alpha-iminopyridine rare-earth metal amido complexes showed high catalytic activities for the dehydrogenation coupling reaction of hydrosilanes and amines providing a variety of silylamines in high yields.