Palladacyclic Complexes Bearing Four-membered Ring Diimine Ligands with Different Functionalities as Catalysts in Suzuki and Heck ReactionsMagnesium Anilido-Oxazolinate Complexes as Catalysts for Ring Opening Polymerization of L-Lactide

• Main Authors: Ming-Tsz Chen, 陳銘賜
• Other Authors: Chi-Tien Chen
• Format: Others
• Language: en_US
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/43043357143502906268

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.