Synthesis Of Lanthanide Amides Supported By Phenoxy(quinolinyl)amide Ligand And Their Catalytic Behavior For Polymerization

Lanthanide chloride, heterobimetallic complexes of lanthanide and alkali metals,lanthanide amides and mixed-valent lanthanide complexes supported byphenoxy（quinolinyl）amide ligand were synthesized. All the complexes have been wellcharacterized. Furthermore, catalytic behavior of some of these complexes for theguanylation of amines and polymerization of caprolactone/lactide were studied. Themain contents were listed below:1. Reactions of3,5-But2-2-（OH）-C₆H₂CH-NH-8-C₉H₆N （LH₂） withLn[N（TMS）₂]₃（μ-Cl）Li（THF）₃afforded heterobimetallic “ate”-complexesL₂LnLi（THF）₂（Ln=Yb（1）, Sm（2））. The two complexes were characterized byelemental analysis, IR and crystal structure determination.2. Reactions ofnBuLi with LH₂in a2:1molar ratio in THF and then droppedslowly into LnCl3pre-activitied by tetrahydrofuran, gave phenoxy（quinolinyl）amidoytterbium chloride [LYbCl（THF）]₂（3）. Complex3was characterized by IR, elementalanalysis and single crystal X-ray diffraction.3. Reactions of complex3with1equivalent of NaN（SiMe3）2in THF affordedheterobimetallic “ate”-complex L₂YbNa（THF）₂（4）. Further study revealed that complex4could also be prepared by the salt metathesis reaction of YbCl₃and LNa2in high yield.Complex4has been well characterized by elemental analysis, IR and crystal structuredetermination.4. Amine elimination reactions of LH₂with Ln[N（TMS）2]3（THF）2in a1:1molarratio in toluene gave monoamido lanthanide complexes LLn[N（TMS）₂]DME （Ln=Sm（5）, Nd（6）, La（7））. Complexes5-7were characterized by IR, elemental analysis, andNMR spectroscopy in the case of complex7. Structural determination revealed thatcomplexes5-7have monomeric structure. 5. The same amine elimination reactions of LH₂with Ln[N（TMS）₂]₃（THF）₂（Ln=Yb, Eu） afforded unexpected mixed-valent trinuclear complexes L₄L^III₂Ln^II（Ln=Yb（8）, Eu（9）） and the dinuclear complex L₃Yb^Ⅲ₂（10）. These complexes have been wellcharacterized by elemental analysis, IR and crystal structure determination.6. Complexes5-7were found to be efficient catalysts for the ring-openingpolymerization of ε-caprolactone and L-lactide under mild conditions to give thepolymers with high molecule weight and narrow molecular weight distribution. Thesecomplexes can also initiate rac-lactide polymerization with good activity, but thestereoselectivity is not high.7. The catalytic behavior of complex4for the addition of aromatic amines tocarbodiimides was explored. It is found that the reaction time, temperation, dosage ofcatalyst, and substituents of the amine are greatly effect on the guanylation.