The Synthesis And Characterization Of New Organic - Inorganic Hybrid Network Structure Materials

Organic-inorganic hybrid framework compounds,including both metal-organic frameworks(MOFs)and extended inorganic hybrids have recently developed into all important new class of solid-state materials.These materials have been intently investigated due to their structural diversities as well as potential applications in areas such as gas separations and storage,heterogeneous catalysis,and photoluminescence.In this dissertation,we have focused our study on the syntheses,structures and properties of two classes of organic-inorganic hybrid materials:metal phosphates incorporating organic ligands and open-framework metal phosphonates.We have prepared more than 40 new organic-inorganic hybrid materials by using different organic ligands,and analyzed their structures as well as explored their properties. These results will be introduced from the following issues.In chapter 2,we explored the synthesis and structures of open-framework metal phosphates incorporating organic ligands.Eight organic-inorganic hybrid gallium oxalate-phosphates,including five structures based on the same Ga₄(PO₄)₄(C₂O₄) building unit(GaPC-1-5),two layered structures(GaP(ox)-6,7)and three-dimensional(3-D)structure(GaPCO-8)with 16-membered ring(MR)channels, have been synthesized by using 1,3-diaminopropane,ethylenediamine and diethylene triamine as structure-directing agents(SDA)under hydrothermal condition. GaPC-1 is layered structure where the building units link together in the same orientation.Corner-sharing of these similar layers result in 3-D GaPCO-2 structure. However,in GaPCO-3,the building units arrange in a wave-like way to generic two types of 8MR channels.GaP(ox)-4,5 contain the layers where the building units have an opposite orientation.Those layers are linked by H₂PO₄ group and Ga(PO₄)(H₂O)₃ cluster,respectively,to form 3-D frameworks with 12MR large pore channels.An open-framework zinc phosphate containing 1,4-benzenedicarboylate(BDC), named as ZnP(BDC),Was successfully synthesized by using phosphoric acid triethyl ester and phosphoric acid triebutyl ester under solvothermal condition despite of the difficulty of incorporating two different organic and inorganic anions.ZnP(BDC)is 3-D structure in which the zinc phosphate layers are pillared by the organic ligands.It exhibits 1-D channels of 15×10 A along c axis.We occasionally obtained two MOFs of zinc benzenedicarboylate(ZnBDC)and zinc isosonicotinate(ZnISN)during the synthesis of ZnP(BDC).ZnBDC is layered structure generated by linkage of the phenyl groups and paddle-wheeled SBUs.ZnISN shows a triple impenetrate diamond network.To construct a zeolite-like organic-inorganic framework,we used imidazole(im)as organic ligand due to the similarity of M-im-M angle with T-O-T angle in zeolites.A new layered zinc phosphate ZnP(im)-1 in which the imidazole acts as a mono-ligand and a mixed-metal phosphate ZnNiP(im)-4 with sandwich-like structure were obtained.In chapter 3,several open-framework metal phosphonates were synthesized by using different phosphonic acids as ligand and structurally characterized.The phosphonic acids include phosphonoacetic acid(H₃pat),3-phosphonopropionic acid (H₃ppn),N-(phosphonomethyl)iminodiacetic acid(H₄pmida)and N,N'-piperazine(bismethylene phosphonic acid)(H₄pbp).A novel 3-D mixed-metal phosphonates,named as ZnNipat-1,was obtained under hydrothermal condition by the reaction of zinc acetate,nickel acetate,H₃pat and 4,4'-bipyridine(4,4'-bpy).The structure contains 5×7 A dimension lozenge shaped 1-D open channels along the [101]direction.Two analogies of zinc and cobalt phosphonoacetes were prepared by using 4,4'-bpy as a second ligand.Another zinc phosphonoacetes with CrB₄ topology was obtained by using the weak alkali of urea.The reaction of H₃pat and manganese acetate results in Mnpat-6 which shows the potential as magnetic material.Hydrothermal reaction of nickel acetate with 3-phosphonopropionic acid and 4,4'-bipyridine resulted in four novel nickel phosphonate compounds.The self-assemblies between the ligands and metal ion result in layer(Nippn-1,3)and chain(Nippn-2,4)structures.Magnetic measurement of Nippn-1 indicate there are ferromagnetic couplings between adjacent Ni²⁺ions(C=1.29 cm³mol^-1K andθ= 2.25K).By using H₄pmida as a chelating ligand,a cluster Was generated and further linked into layered Znpmida and chain structure Nipmida.Two novel zinc phosphonates were synthesized by using H₄pbp as ligand and 1,3-propanediamine and Na⁺ as SDAs. Both of them show pillar-layered structures in which the "zinc phosphate" layers are linked by the organic moieties into 3-D frameworks.The SDAs are located in the channels.One of our interests is to prepare hybrid materials with zeolite topologies by using 4-connected organic ligand.A novel phosphonic acid,that is 4-phosphono-benzoic acid(H₃pbc),was designed and successfully prepared along this object.Fourteen zinc phosphonates,named as Znpbc-1-14,were synthesized by the mixed solvothermal reaction of zinc acetate and H₃pbc by using different ratios of metal:ligand,SDAs and the solvents in N,N-dimethylformamide(DMF)and water.Znpbc-1 shows 3-D zeolite-like structure in which the zigzag chains are linked by the organic moieties.It is found that Znpbc-1 can transform into Znpbc-2,3 by both solution-mediated and solid-state processes.A possible mechanism for the transformation was proposed.Gas sorption studies show that Znpbc-1 has accessible pores for methanol and water and exhibits size-selectivity for alcohols.The structures of Znpbc-4,5 are constructed by double crankshaft chains and organic linkers,which adopt a topology of zeolite GIS.It is first time that such a topology is observed in the metal phosphonate system.The SDA of triethylene tetramine results in another two zeolite-like structures Znpbc-6,7.Znpbc-6 show a novel topology with distorted double crankshaft chain,while the structure of Znpbc-7 is(4,6,12)-sheet pillared by organic linkers,which shows a topology of zeolite SOD consisting ofβcages.Three pillar-layered structures of Znpbc-8-10 were synthesized by using low charge-density amines as SDAs.However,when ethylenediamine and 1,3-diaminopropane were employed,they act as second ligand to coordinate with zinc atoms,result in pillar-layered structure of Znpbc-11 and(4,2)-connected zeolite-like structure of Znpbc-12.Znpbc-13,14 were synthesized by using 2,2'-bipyridine (2,2'-bpy)as second ligand.In structure Znpbc-13,the zinc phosphate chains consisting of 3- and 4-MR are linked by the organic ligand into 3-D structure with 12-MR square channels.Structure Znpbc-14 contains zigzag layers which interact with each other byÏ€-Ï€stacking.These results show that the organic amines are important in the formation of compounds Znpbc-1-14,which can act as templates,as structure-directing agents,as second ligands or in a dual role.