Summary: | 博士 === 國立中興大學 === 化學系所 === 96 === The thesis discusses some palladacycles and magnesium complexes applied in catalytic reactions. For convenience and better understanding, the thesis is divided into two parts. The first part describes palladium-catalyzed reactions and the second part deals with ROP reaction catalyzed with magnesium complexes.
Part one-A: Preparation of novel unsymmetrical, tridentate sulfur-containing ligand precursors, PhN=C(CMe2)(NPh)C=N(CH2)2SR [R=CMe3, Ph] are described. Reaction of ligand precursors with one molar equivalent of Pd(OAc)2 yields palladium(II) complexes, [PhN=C(CMe2)(N-η1-Ph)C=N(CH2)2SR]Pd(OAc). Treatment of orthometallated palladium(II) acetate complexes with excess of LiCl in methanol gives the complexes [PhN=C(CMe2)(N-η1-Ph)C=N(CH2)2SR]PdCl. Molecular structures have been determined by X-ray diffraction. The application of those novel palladacyclic complexes to the Suzuki and Heck reactions with aryl halide substrates was examined.
Part one-B: Four new ligand precursors, PhN=C(CMe2)(NPh)C=N(E) [E =(CH2)2OMe, CH2C(=O)OMe, (CH2)2CH3, and C6H5] are reported. Treatment of ligand precursors with one molar equivalent Pd(OAc)2 in THF or CH3CN affords aceto-bridged palladium(II) complexes, [{PhN=C(CMe2)(N-η1-Ph)C=N(E)}Pd(OAc)]2, as di-nuclear palladium complexes. Reactions of Palladium(II) complexes with excess saturated NaCl(aq) in acetone afford orthometallated dimer or monomer palladium(II) complexes, as [{PhN=C(CMe2)(N-η1-Ph)C=N(CH2)2CH3}PdCl]2 or [PhN=C(CMe2)(N-η1-Ph)C=N(E)]PdCl. The crystal and molecular structures are reported and the catalytic activities of these palladacycles toward the Suzuki and Heck reactions are investigated.
Part two: A new series of mononuclear magnesium complexes of type L2Mg (where L = anilido-oxazolinate ligands bearing different functional groups) has been prepared. The activities of magnesium complexes toward the ring opening polymerization of L-lactide have been investigated. Experimental results show that L2Mg complexes efficiently initiate the ring-opening polymerization of L-Lactide in the presence of benzyl alcohol and yielding polymers in a controlled fashion.
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