| A series of phenoxy-amido rare-earth metal complexes supported by the dianionic phenoxy-amido ligands were synthesized. The catalytic activities of anionic phenoxy-amido for the amidation of aldehydes with amines and of neutral phenoxy-amido rare-earth metal amide for the guanylation of amines with carbodiimide were examined.The aminophenol ligands used in this thesis are as follows:N-p-fluoro-phenyl(2-hydroxy-3,5-di-tert-butyl)benzylamine [NO]1H2,N-p-methyl-phenyl(2-hydroxy-3,5-di-tert-butyl)benzylamine [NO]2H2,N-p-chloro-phenyl(2-hydroxy-3,5-di-tert-butyl)benzylamine [NO]3H2,N-p-bromo-phenyl(2-hydroxy-3,5-di-tert-butyl)benzylamine [NO]4H2,N-p-methoxyl-phenyl(2-hydroxy-3,5-di-tert-butyl)benzylamine [NO]5H2The main results obtained are as follows:1. The anionic rare-earth metal amido complexes stabilized by phenoxy-amido ligand [NO]21Ln[N(TMS)2][Li(THF)]2 [Ln = Y(1), Yb(2), Sm(3), Nd(4)], [NO]22Sm[N(TMS)2][Li(THF)]2 (5), [NO]23Sm[N(TMS)2][Li(THF)]2 (6), [NO]24Sm[N(TMS)2][Li(THF)]2 (7) were prepared according to the literature in high isolated yields. It was found that complexes 1-7 are active catalysts for amidation of aldehydes with amines. The new catalysts show high activity and a wide range of scope to produce amides in good to excellent yields under mild conditions. A cooperation effect between lanthanide and alkali metals for high activity is proposed.2. The catalytic activity of some lanthanide-potassium heterobimetallic complexes stabilized by carbon-bridged bis(phenolate) ligand for amidation of aldehydes with amines were also tested. It was found that the ionic radii of the lanthanide metals have a significant effect on the catalytic activity. Although the conditions are a litter rigorous, the catalysts show a wide rang of scope to produce amides.3. Reaction of of Ln[N(TMS)2]3(μ-Cl)Li(THF)3 with the lithium aminophenoxy in 1:2 molar ratio generated in situ in tetrahydrofuran (THF) gave the anionic rare-earth metal complexes [NO]35Ln[Li(THF)]3 [Ln = Y(13), Yb(14), Sm(15), Nd(16)]. Complexes 13-16 were fully characterized by IR and elemental analysis and single crystal X-Ray diffraction. Structural determination revealed that they are isostructural.4. Reaction of of Ln[N(TMS)2]3(μ-Cl)Li(THF)3 with aminophenol [NO]5H2 in 1:1 molar ratio in THF gave the neutral phenoxy-amido rare-earth metal amide {[NO]5Ln[N(TMS)2](THF)}2 [Ln = Sm(17), Nd(18), La(19)], whereas an ion-pair rare-earth metal complexe [{NO}35Yb2(μ-Cl)(THF)2][Li(THF)4] (20) was isolated under the same reaction conditions when Yb[N(TMS)2]3(μ-Cl)Li(THF)3 was used as starting materials. Complexes 17-20 were fully characterized by IR and elemental analysis and single crystal X-Ray diffraction.5. Complexes 17-19 serve as excellent catalyst precursors for catalytic addition of various primary amines to carbodiimides, efficiently providing the corresponding guanidine derivatives with a wide range of substrates under solvent-free condition. The reaction shows good functional groups tolerance. |
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