New Open Metal Phosphonic Acid Coordination Polymer Synthesis And Structure

Coordination polymer is a compound with periodic network structure which is constructed by small molecular ligands and metal ions or clusters through self-assemble process. As an important new kind of porous material, it is more controllable in pore size and shape and the synthesis condiction is mild. These materials have been intently investigated due to their structureal diversities as well as potential applications in areas such as catalysis, separations, storage, photoluminescence, magnetism and nonlinear materials.In this dissertation, we have focused our study on the syntheses, structure and properties of metal phosphonates with a novel phosphonic acid ligand, 3-phosphono-benzoic acid (H₃pbc). We have prepared 13 new metal phosphonates with H₃pbc ligand, analyzed their structures and properties as well as the synthese disciplinarian.Aimed to prepare metal phosphonates with zeolite topologies, we used 4-connected Zn(Ⅱ) metal center and 4-connected H₃pbc ligand to synthesis metal phosphonates. Five zinc phosphonateds, [Zn(Hpbc)]·1.5H₂O (CPP-1), [Zn_2.5(pbc)₂(H₃O)] (CPP-2), [Zn₂(Hpbc)₂(H₂O)]·2H₂O (CPP-3), [Zn_1.5(pbc)(4,4`-bpy)<sub>0.5</sub>(N(CH<sub>3</sub>))<sub>0.5</sub>]·H<sub>2</sub>O(Cpp-4), [Zn<sub>3</sub>(pbc)<sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>]·2H<sub>2</sub>O (Cpp-5), were prepared by the mixed solvothermal reaction of zinc acetate and H<sub>3</sub>pbc. Zn<sub>2</sub>P<sub>2</sub> four-menbered rings formed by conner-shared ZnO<sub>4</sub> and CPO<sub>3</sub> tetrahedrons are found in Cpp-1 to Cpp-3. Different connected ways of these Zn<sub>2</sub>P<sub>2</sub> four-menbered rings lead to different structure in Cpp-1 to Cpp-3. Cpp-1 shows 3D zeolite-like structure with MER topology in which double crankshaft chains formed by Zn<sub>2</sub>P<sub>2</sub> four-menbered rings are linked by the organic moieties. Edge-shared Zn<sub>2</sub>P<sub>2</sub> four-menbered rings form a 3D structure with RHO topology in Cpp-2. Cpp-3 is constructed by organic linkers and zigzag chains formed by conner-shared Zn<sub>2</sub>P<sub>2</sub> four-menbered rings. Cpp-4 is an interesting four layered structure with both H<sub>3</sub>pbc and 4,4`-bpy ligand. Zonal zinc phosphate structure is found in Cpp-5.four novel metal phosphonate, [Pb(Hpbc)] (Cpp-6), [Pb₃(pbc)₂(H₂O)₂] (Cpp-7), [Cd(H₂pbc)₂(H₂O)₂] (Cpp-8), [Cd_1.5(pbc)(H₂O)_1.5]·0.5H₂O (Cpp-9) have been successfully synthesized by pH-dependent hydrothermal/solvothermal reaction of lead/cadmium salts and 3-phosphono-benzoic acid. A variety of coordination modes of H₃pbc along with different metals results in rich structures range from one dimension to three dimension. We can easily find the structural response on pH value of the reaction. Our study demonstrates that the structural diversity of metal phosphonate materials can be realized by the use of novel multi-functional ligand and adjustment of the pH value of the reaction.Hydrothermal reaction of transition metal acetate with 3-phosphono-benzoic acid resulted in three new metal phosphonates, [Cu₃(pbc)₂(H₂O)]·4H₂O (Cpp-10), [Co₈(pbc)₄(OH)₄(H₂O)₃]·7H₂O (Cpp-11), [Ni₆(pbc)₄(H₂O)₃]·2H₂O (Cpp-12). Cpp-10 has a rare structure consist of helix inorganic chains and organic linkers, and it is synthesized under a completely achiral condition. Cpp-11 is a tranditional pillar-layered structure. An interesting struture constructed by 2D inorganic layers, metal clusters and organic linkers was observed in Cpp-12.We have also tried to synthesize metal phosphonate with rare-earth metals due to their special properties and diversity of coordinated mode and seccussfully prepared a metal phophonate with La, [La(H₂pbc)₃(H₂O)₄] (Cpp-13).