Solution Synthesis And Properties Of Coordination Polymer Micro/Nanomaterials With Carboxylate-Containing Ligands

During the last decade,coordination polymer micro/nanomaterials have attracted considerable attention not only because of their intriguing varieties of compositions and morphologies,but also due to their potential applications in gas sorption,sensor,catalysis,drug delivery,and so on.The small size and specific morphology-dependent properties make coordination polymer micro/nanomaterials more attractive for the applications in some specific fields compared with bulk coordination polymers,which have been investigated over the past two decades.In addition,coordination polymer micro/nanomaterials can also be used as precursors to prepare metal oxides,metal sulfides,alloys,metal/carbon composite materials etc under certain conditions.More importantly,in some cases,metal oxides obtained via thermal decomposition method using coordination polymer micro/nanomaterials as precursors can not only keep their original morphologies,but also can have hollow structures.In this thesis,four ligands with carboxylate groups,namely benzene-1,4-dicarboxylic acid(1,4-H2BDC),benzene-1,3-dicarboxylic acid(1,3-H2BDC),4,4'-biphenyldicarboxylic acid(H2BPDC),benzophenone-4,4'-dicarboxylic acid(H2BPnDC)were used to react with metal salts to give five coordination polymer micro/nanomaterials.All the complexes were characterized by X-ray powder diffraction(XRD),energy dispersive spectrometry(EDS),field emission scanning electron microscopy(SEIM),transmission electron microscopy(TEM),thermogravimetric analysis(TGA)and so on.Solid state thermal transformation properties of these coordination polymer micro/nanomaterials were studied in detail.There are five main parts in this thesis:1.Well-dispersed hierarchical straw-sheaf-like architectures of[Gd(1,4-BDC)1.5(H2O)2]were successfully synthesized via an ultrasonic-assisted solution-phase method using Na2BDC and Gd(NO3)3·6H2O as the reactants and polyvinylpyrrolidone(PVP,30K)as the surfactant.Systematical investigations have been proceeded on the factors influencing the morphology of[Gd(1,4-BDC)1.5(H2O)2]nanostructures,such as the concentrations of Na2BDC and Gd(NO3)3·6H2O,the ultrasonic time and power,as well as the amount of PVP.A possible mechanism responsible for the formation of hierarchical architectures was proposed.The as-obtained Eu3+-and Tb,?-doped[Gd(1,4-BDC)1.5(H2O)2]products show strong characteristic red and green emissions under ultraviolet excitation.Furthermore,the straw-sheaf shaped Gd2P3 could be obtained via thermal decomposition method and using[Gd(1,4-BDC)1.5(H2O)2]complex as the precursor.2.Shape-controlled synthesis of cobalt(?)-based coordination polymer particles were synthesized via a directly mixed approach using Na2BPDC and Co(NO3)2-6H2O as the reactants in the ethanol-water mixed solvent.Three different structures of flower-like architectures,multilayer stacked structures and nanosheets were synthesized by varying the volume ratio of ethanol and water.Phase-pure CO3O4 nanocrystals were obtained by annealing the coordination polymer particles without significant alterations in morphology.The catalytic effect was investigated for the CO3O4 nanocrystals with different morphology on the thermal decomposition of ammonium perchlorate(AP)and it was found that the CO3O4 nanosheets had the highest catalytic activity.The specific surface areas of CO3O4 nanocrystals were measured by Brunauer-Emmett-Teller(BET)technique and the results showed that the catalytic activity of CO3O4 nanocrystals for the thermal decomposition of AP increased with the BET specific surface area and pore volume increasing.3.Indium(III)-benzendicarboxylate(In-BDC)hexagonal rods with different sizes were synthesized via a simple solution reaction,using indium(III)nitrate and 1,4-benzenedicarboxylic acid as the starting reactants,sodium acetate as the modulator,and N,N-dimethylformamide(DMF)as the solvent.Three different sizes of hexagonal rods,hexagonal lumps and hexagonal disks were synthesized by varying the concentration of reactants.In2O3 hollow structures were prepared by annealing In-BDC complexes.It was found that the amount of sodium acetate was important in determining the size of In-BDC hexagonal rods as well as the formation of In2O3 hollow structures.In addition,In2O3 hollow structures were further studied by Raman spectrum and room-temperature photoluminescence.4.Indium(?)benzophenone-4,4'-dicarboxylate(In-BPnDC)sub-microspheres were successfully synthesized via a simple solvothermal method using indium(III)nitrate and benzophenone-4,4'-dicarboxylic acid as the reactants and DMF as the solvent.Porous yolk-shell structured In2O3 were prepared by annealing In-BPnDC complexes.The BET specific surface area of the as-obtained In2O3 is 33.17 m2/g and it has a mesoporous structure from nitrogen adsorption-desorption investigation.In addition,Raman and room-temperature photoluminescence spectra of In2O3 yolk-shell structures were also studied.5.Large-scale indium-based coordination polymer particles(In-CPPs)were synthesized through a solvothermal process using indium(III)nitrate and isophthalic acid as the reactants and DMF as the solvent.In-CPPs were comprised of honeycomb-like nanostructures which were made of abundant nanoplates.It was found that In-CPPs had porous structures and high BET specific surface area.Zeta potential of the products indicated that in aqueous solution the as-obtained In-CPPs were positively charged on the surface.The as-obtained products were used as adsorbents in waste-water treatment,and showed very good ability to rapidly remove Congo red.