The synthesis and characterization of dimeric rareearth amides stabilized by a dianionic N-aryloxo functionalized β-ketoiminate ligand are described.Reactions of 4-(2-hydroxy-5-methyl-phenyl) imino-2-pentanone(LH2) with Ln[N(SiMe3)2]3(μ-Cl)Li(THF)3 in a 1:1 molar ratio in THF gave the dimeric rare-earth amido complexes [LLn{N(SiMe3)2}(THF)]2 [Ln = Nd(1),Sm(2),Yb(3),Y(4)].These complexes were well characterized,and the definitive molecular structures of complexes 3 and 4 were determined.It was found that complexes 1― 4 can initiate the ring-opening polymerization of ε-caprolactone,and the ionic radii of the central metals have significant effect on the catalytic activity.
HAN XiangZong WU LiangLiang YAO YingMing ZHANG Yong SHEN Qi
Reaction of homoleptic yttrium tris-alkyl complex YR3 (R=CH2C6H4NMe2-o) with 1 equivalent of amine bis(phenol)s LH2 (L=Me2NCH2CH2N(CH2-(2-O-C6H2-But2-3,5))2) afforded the solvent-free yttrium alkyl complex LYR (1),which has been characterized with elemental analysis,1H NMR and IR spectra,and structural determination. The coordination geometry around the center metal atom can be best de-scribed as a distorted octahedron. It was found that complex 1 can be used as an efficient catalyst for the Tishchenko reaction.
The lanthanide complexes containing a bulky tridentate [N,N,O] Schiff base ligand 3,5-But2-2-（OH）C6H2CH=N-8-C9H6N （HL） were synthesized and characterized. The reaction of anhydrous LnCl3 with NaL formed in situ in a 1：1 molar ratio in THF at room temperature afforded the lanthanide Schiff base dichloride complexes LnLCl2（DME） （Ln=Eu （1）; Sm （2））. Complexes 1 and 2 can be used as precursors for the synthesis of the lanthanide cyclopentadienyl Schiff base derivatives. The reactions of complexes 1 and 2 with one equiv of NaCH3C5H4 in THF provided the desired products LnL（CH3C5H4）CI（THF）.THF （Ln=Eu （3）; Sm （4）） in good isolated yields. These complexes were characterized by elemental analysis, IR spectra, and X-ray structural determination, in the case of complexes 3 and 4. The crystal data of complex 3 are monoclinic, P21/C space group, a=1.3370（2） nm, b=1.5190（2） nm, c=1.8910（3） nm, β=109.846（4）°, V=3.6125（8） nm^3, Z=4, Dc=1.416 mg/m^3,μ=1.847 mm^-1, F（000）=1584, R=0.0707, wR=0.1350. The crystal data of complex 4 are monoclinic, P21/c space group, a=1.3383（1） nm, b=1.5210（2） nm, c=1.8960（2） nm, β =109.878（3）°, V=3.6293（7） nm^3, Z=4, Dc=1.407 mg/m^3, μ=1.728 mm^-1, F（000）= 1580, R=0.0670, wR=0.1385.
Yttrium complexes stabilized by a diaminobis(phenolate) ligand were synthesized and their catalytic behavior was explored. Reaction of YCl3 with 1 equiv of LNa2 [L= Me2NCH2CH2N{CH2-(2-O-C6H2-tBu2-3, 5)}2] gave the yttrium chloride LYCl(THF) (1) in 92% yield. Complex 1 can be used as starting material to prepare the yttrium amido derivative. Complex 1 reacted with 1 equiv of LiNPh2 in THF to afford the expected yttrium amido complex LYNPh2 (2) in high yield. Both of complexes 1 and 2 have been well detected by elemental analysis, NMR spectra and single-crystal X-ray analysis. It was found that complex 2 can efficiently initiate the ring-opening polymerization of L-lactide and ε-caprolactone, and a controlled manner is observed in the former case.
SONG FengKui YAN ChunHui SUN HongMei YAO YingMing SHEN Qi ZHANG Yong
