Study On The Synthesis, Characterization And Performance Of Schiff Base Functionalized Metal Coordination Polymers

Coordination chemistry provides us large number of interesting and useful complexes by the use of organic ligands containing hetero atoms as coordination sites.Schiff bases are a class of organic ligands having a C=N double bond,usually formed by a condensation reaction between a class of substances containing an active carbonyl group and another substance containing an amine group.Since Schiff base compounds contain various heteroatoms such as nitrogen,oxygen and sulfur with strong coordination ability,as well as their structural specificity and functional diversity,they are coordinated with different transition metals to synthesize the Schiff base functionalized coordination complexes.Schiff base functionalized coordination polymers are widely used in analytical chemistry,electrochemistry,functional materials,biomedicine and catalysis are all well applied.Therefore,a fascinating research topic is devoted to the synthesis and application of novel Schiff base ligands and their metal complexes.The study in the master thesis is related to the preparation of Schiff base functionalized coordination complexes and their applications for catalysis and supercapacitors.The main content is as follows:1.The ligand L with a Schiff-base functional group is obtained by reacting3-hydroxy-4-aminobenzoic acid with para-benzaldehyde.The coordination polymer microspheres?Zn-L-CP?with a hierarchical microporous-mesoporous-macroporous structure and core-shell structure are obtained by mixing the ligand L and zinc nitrate hexahydrate together under hydrothermal conditions.The obtained Zn-L-CP microspheres are proved to be effective heterogeneous catalyst for the deacetylation reaction with the merits of easy recycling and stable.We use the core-shell Zn-L-CP polymer microspheres as a heterogeneous catalyst,the catalytic deacetylation reaction has good catalytic performance?60°C,methanol as solvent,yield 96%?.The recycling of the Zn-L-CP microspheres for catalytic deacetylation under optimal condition is studied,and the catalytic effect of the Zn-L-CP heterogeneous catalyst is proved to have no significant loss?the yield of 2-pyridinol remained above 90%?after using in seven reactions.2.The Schiff base functionalized cobalt-based metal polymer microspheres with urchin-like structure are synthesized by hydrothermal method under the optimal conditions,and they are used as electrode materials for supercapacitors.The microsphere morphology assembling with nanorod microstructure is observed in the Co-L-180 sample(S_BET=137.23 m² g^-1).In 3M KOH,the Co-L-180 exhibits the specific capacitance of 404 F g^-1,at the current density of 1 A g^-1,and the energy density is 5.9 Wh kg^-11 at the power density of 2915 W kg^-1.More significantly,The Co-L-180 exhibits outstanding cycle stability.The electrode materia is observed to be further activated during the constant charge and discharge cycle,and the capacitance retention rate of Co-L-180 is 131%after 50,000 cycles,even at a relatively high current density of 10 A g^-1.3.We use hydrothermal method to synthesize Schiff base ligands with high nitrogen content of melamine,and then coordinate with cobalt to form nitrogen-doped,porous coordination polymers?Co-PCPs?,which is used as electrode materials for supercapacitors.The nitrogen doping Co-coordination polymer synthesized at 140°C exhibits the maximum specific capacitance of 512 F g^-11 at a current density of 1 A g^-1.Excellent cycle performance is observed.The capacitance value remain 97.4%even after 40000 cycles.More significantly,the Co-coordination polymer exhibits the energy density of 13.27 Wh kg^-11 at a power density of 2913 W kg^-1.