Synthesis And Structural Characterization Of New Metal Phosphites Microporous Material

The open-framework inorganic materials with novel channel structures arereceiving more interests for their wide application as catalysts, absorbents,ion-exchangers, transducers and photoelectric materials. Recently, following thedevelopments of nano-technology, more and more zeolite-type open- frameworkmaterials with different pore size, from nanometer to sub- micrometer, are utilized asmicrorectors to prepare metal and non-metal nano-particles and rods (wires) by thesize-effects of their uniform nano-cavities and channels, such as ALPO-n,mesoporous materials. Additionally, The ordered porous structures of openframework materials give a promising chance to assemble nano-particles and toexploit novel functional composite materials. It is well known that some transitional metal ions play an important role in suchcatalytic reactions as redox, photochemical and free-group reactions, so the inorganicmaterials with open frameworks including transitional metals appear to be important.To this day, the study on transitional metal phosphates has still been increasing.Recently, much work has been carried out to prepare inorganic open-frameworkmaterials with new compositions or topologies by substituting phosphite, arsenates,germantes, selenates, sulfates and carbonate for phosphate. It showed from theresults reported that the source materials as phosphite, arsenates, germantes,selenates, sulfates and carbonate can extend open-framework materials fromstructural, compositional, functional aspects. For example, such phosphites asmanganese, zinc, vanadium, iron and cobalt phosphite can possess some newstructural type, can also bring about more potential application in magnetism, optics,electron conduction and catalysis. Based on the new trends on the replacement of phosphate by other inorganicacids, we chose phosphite reported a little as the replacer of phosphate and focusedon the synthesis of transitional metal phosphite open-framework materials whichhold the large cavity (channels), new composition and structure. In the dissertation,some transitional metal phosphite compounds with new structural types have beensynthesized and characterized. The hydrothermal reactions of zinc acetic, phosphite, piperazine and wateryield 1D chain (C4H8N2H4)[Zn(HPO3)2](Ⅰ) and 3D network(C4H8N2H4)[Zn3(HPO3)4] (Ⅲ). And structural investigation suggests that theframework of both compounds is also built from ZnO4 tetrahedron and HPO3pesduo-tetrahedron by sharing vertex and hold intact four-ring {Zn2P2O4} chains.The difference of the two compounds origin from different Zn: P ratio in the anionframework, so the same organic template can result in the different structures ofphosphite compound. In the water/ethanol/NH4F system, a kind of 2D layered [H3N(CH2)2NH3][Zn2(HPO3)3](Ⅱ) can be synthesized from zinc acetic and phosphite by usingen and IMD as templates under hydrothermal condition. Structural solution indicatesthat the anion inorganic layer with (4,8) rings is built from the four-ring {Zn2P2O4}zigzag ladder chains linked by pseudo-tetrahedron HPO3, which diprotonated enlocated in the channels of eight-member-rings. The Zn to P ratio of the anion layer is2/3 is further indicated by elemental analysis Using metal cobalt and zinc as source materials, and piperazine as template, wefirst prepared the double metal phosphite (C4H8N2H4)[Zn(3-x) Cox(HPO3)4(H2O)2](x≈0.83) (Ⅳ) by hydrothermal treatment, which holds new composition and structure.The 3D framework of the compound is constructed by alternately linking MO4 (M =Zn or Co) tetrahedron, ZnO4(H2O)2 octahedron by sharing vertex ofpseudo-tetrahedron HPO3. It is noted that the infinite chains comprised of four-ringM2P2O4 in the compound(Ⅳ) are alike to those in the compounds(Ⅰ) and (Ⅲ). Dueto the non-abound d orbit of the cobalt atom, the compound(Ⅳ) hold interestingmagnetism and potential catalysis prop...