Synethesis And Properties Of Early Transition Metal Complexes Containing Pincer Oxazoline Ligands

Bisoxazolines and tridentate NNN Pybox pincer ligands are important ligands in organometallic chemistry with broad application in homogeneous catalysis and asymmetric synthesis. Typically, these ligands are good σ-donors, weak π-acceptors and can be easily modified to attain the desired steric, bulkiness- or electronic properties. Herein, several oxazolines-based ligands have been synthesized to obtain series of Binuclear and mononuclear complexes with early transition metal such as copper, zinc, cadmium and nickel. Moreover,the solid state structures of the complexes have been characterized by single crystal X-ray diffraction. In order to study the structure-function relationship between oxazolines-based complexes and the catalytic reactions, we used the synthetic complexes catalyze a variety of organic reactions. This thesis mainly includes the following chapters:In Chapter 1, the background and significance of this thesis have been described which puts emphasis on catalyzing reaction field catalyzed by oxazoline-based complexes. At last, the content and innovation of the paper were also discussed.In Chapter 2, two binuclear and mononuclear cadmium(II) complexes were synthesied and characterized which contained oxazoline-based ligands. The interaction among molecular and all crystal structures were discussed in detail. Moreover the properties of those two cadmium(II) complexes have been explored in catalyzing C-N coupling reaction between halogenated benzene derivatives and two primary amine.In Chapter 3, three crystal structures of oxazoline-based zinc complexes were obtained which containing different halogen ion(chlorine, bromine or iodine). The catalytic activity of the compounds was studied in catalyzing hydrolysis of 4- nitrophenyl acetate, we also compared the effects of different halogen ions on the catalytic hydrolysis effect. Furthermore we used pH potentiometric titration determine the stability constants and species distribution of zinc complexes in aqueous.In Chapter 4, four oxazoline-based copper complexes were synthesized, we explore their properties in catalyzing the coupling of α-carbonyls with functionalized amines and α- oxyacylation of ketones. The results showed these copper complexes have high catalytic effect.In Chapter 5, two crystal structures of zinc(II) complexes containing two different pyridyl oxazoline-based pincer ligands have been determined by singal crystal X-ray diffraction; Furthermore the effect of ligand substituents on zinc(II) complexes were studied in catalyzing the Knoevenagel condensation reaction between active methylene compounds and ferrocenecarboxaldehyde.In Chapter 6, the pyridyl oxazoline-based nickel(II) complexes were synthesized in solid. To our delight, three new five- and six-coordinated nickel(II) complexes were obtained which contained the solvent molecules(water or methanol). The transformation of balance between complexes and solvent molecules were discussed in detail, and each crystal structure of the synthetic complexes was described.