Synthesis, Characterization And Catalytic Activity Of Mononuclear And Polynuclear Complexes

The studies of design, synthesis and catalytic properties are important projects in the field of coordination chemistry. The synthesis, characterization and catalytic activities of mononuclear and polynuclear complexes have great role for producing high value fine chemicals by using the cheap, easily accessible, and environmental friendly oxygen as oxidant. They are also important both in the treatment of radioactive waste and illustration the essence of active metal center embedded in enzyme as well as probing vital processes.128 novel coordination complexes in three systems were synthesized in this report. The three system are: (1) mononuclear and trinuclear complexes of oxamido or bis-oxamide, (2) mononuclear and polynuclear complexes of asymmetric oxamide,; (3) uranium ^ thorium or lanthanide complexes of schiff bases. The correlation between spectroscopic properties and molecular structures was discussed, and the oxidation catalytic activities of the mononuclear and polynuclear complexes were studied.The characteristics of this study in synthesis are as below:(1) Bis-oxamide ligands were prepared from oxamido with different functional groups. Mononuclear complexes of bis-oxamide and oxamido were synthesized. It is the first time to extend oxamido mononuclear complexes to bis-oxamide mononuclear complexes(2) Asymmetric oxamide ligands were synthesized by introducing two amino groups according to their different activity. Establishing a new method to prepare asymmetric oxamide conveniently with high yields, and this method created an advantageous condition for synthesis of mononuclear complexes of asymmetric oxamide.VI(3) Some new development in the synthesis of polynuclear coordination complexes were achieved, such as:Extending the synthesis of oxamide bridged dinuclear complexes to asymmetric oxamide bridged dinuclear complexes. Asymmetric oxamide bridged tetranuclear complexes were prepared by the reaction of mononuclear copper (II) complexes with transition-metal ion.xtending trinuclear copper(II) complexes to bis-oxamides bridged trinuclear copper(II) complexes.eterotrinuclear oxamido bridged complexes were prepared.Based on IR, elemental analyses, electronic spectra, conductivity and thermo analyses, the structures of the complexes were characterized. It was found that those oxamido and bis-oxamide ligands had stronger coordination capacities because of the deprotonated-amino group, which had higher donating property. They could form much stable complexes with transition-metal ions.The catalytic activities of the complexes in the ethylbezene oxidation by oxygen molecule and in epoxidation reaction of unfunctionalized olefins have been studied.Within the momonuclear complexes of oxamido it adopted a planar configuration and the coordination scheme was the familiar tetradetate N2O2, the momonuclear complexes of bisoxamides coordination scheme was the familiar tetradetate N^ mononuclear complexes of bisoxamides were much stable because N4 coordination field was much stronger than that of N2C>2. Within the momonuclear complexes of asymmetric oxamide it adopted a planar configuration and the coordination scheme was the familiar tetradetate NsO.Based on the study of the polynuclear complexes, it was found the coordination structures had the following properties:(1) Trinuclear copper (II) complexes were proposed to have oxamido-bridged or bisoxamide-bridged structures consisting of three copper (II) ions in which each copper (II) ion had a square-planar environment.(2) Hetero trinuclear complexes were proposed to have an oxamido-bridged structure with copper (II) in a planar environment and M (II) (M ?Co, Ni and Mn) in an octahedral environment.(3) Hetero binuclear complexes were proposed to have asymmetric oxamide-bridged structures with copper (II) in a planar environment and M (II) in an octahedral environment.(4) Hetero tetranuclear complexes were proposed to have asymmetric oxamide-bridged structur...