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
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
The synthesis,characterization and luminescent properties of aluminum complexes containing a dianionic N-aryloxo functionalized β-ketoiminate ligand are presented.4-(2-Hydroxy-5-R-phenyl)imino-2-pentanone (R=Me,L 1 H 2;R=tert-butyl,L 2 H 2) ligands reacted with AlEt 3 in tetrahydrofuran to give the aluminum complexes (L 1 AlEt) 2 (1) and (L 2 AlEt) 2 (2) in reasonable isolated yields.X-ray diffraction revealed that complexes 1 and 2 have solvent-free centrosymmetric dimeric structures,and each aluminum center has distorted trigonal bipyramidal geometry.At room temperature,complexes 1 and 2 exhibit blue photoluminescence in acetonitrile with maximum emission wavelengths of 419 and 413 nm,respectively.
