Synthesis And Characterization Of Metal Phosphite And Metal Selenite

There are many remarkable materials fashioned by nature, one of which isformed by the co-existence of inorganic oxides and organic molecules. This uniquestructure results in excellent properties, such as catalytic activity, ion exchange,adsorption, biology activity, piezoelectricity and ferromagnetism. Besides, it is foundthat organic components can dramatically influence the microstructures of inorganicoxides. Based on the above founding, people have tried to synthesize a class of novelfunctional materials with unique structures and properties: inorganic-organic hybridmaterials. In the synthesis of this kind of materials, organic component can influencethe nucleation and growth of inorganic compound, and control the microstructure ofthe inorganic framework. By the interaction of the interface between the organiccomponent and inorganic oxides, the organic molecules can imprint the structureinformation to the inorganic framework and thus obtain a series of hybrid materialswith novel structures and special properties. The diversity of the compositions andstructures of inorganic-organic hybrid materials were derived partially from the hugecompositional and structural combinational from individual inorganic and organiccomponents. Current studies on the hybrid materials mainly concentrate on thefollowing aspects: the template-induced microporous and mesoporous materials,coordination polymers and clusters, and biomineralized systems.Taking into consideration the international studies, we have focused our studyon the influence of the changes caused by the coordination position or conformationof organic component on the structure of inorganic-organic hybrid compound. Wediscuss here the syntheses and structural features of these novel compounds and thestructural relationships among them.The inorganic component of 1 is built up from four rings of HPO3 and ZnO4,sharing vertices, as Zn-O-P. In compound 2, the sheet structure consists of four-andtwelve-membered rings that form a network of alternatively linked corner-sharingpolyhedra. Compound 2 possesses a ladder-like triple unit of 4-membered ringbuilding-unit. Compound 3 contains a 4-, 6-, 8-net sheet with the P-H groups cappingon the six-membered rings and alternating above and below the sheet. Compound 4consists of alternating inorganic and organic layers stacked along [001] direction andthe sheet structure consists of 4-, 8-membered rings. Compound 5 contains ZnO4tetrahedra, ZnO2N3 trigonal bipyramid and HPO3 pseudo pyramids as thepolyhedral-building units. The sheet framework structure of 6 has the similarinorganic frameworks of compound 5 which contains ZnO6, but the connections ofthe Zn atoms are different. In the compound 5 and 6, the connections ZnO2N3 andZnO6 of Zn atoms are the first reported in the synthesis of zincophosphite materials.The hydrothermal reactions gave 7 and 8. They have similar inorganic frameworkswith the same compositions. They are both built up from two-dimensional layerswith four-and eight-membered rings and one-dimensional chains composed offour-membered rings. In compound 9 and 10, the anionic part in the asymmetric unitcan be considered as secondary building units, which are connected to each other viavertex oxygen atoms forming a four, six, twelve-network parallel to the ab plane.The layers are attached along the [010] direction in an -AAAA-sequence to generatethe three-dimensional framework. Compound 11 and compound 12 were synthesizedusing 1-Methylpiperazine and ethylenediamine as templates and characterized bysingle-crystal X-ray diffraction. Both phosphites consist of novel building-units,double 4-membered ring chains for 11 and 4-membered ring chains for 12, which areobserved for the first time in the reported structures of metal phosphites. Compound13 consists of a 16-membered ring in the three-dimensional inorganic framework.A new vanadium phosphite 14 has been prepared under hydrothermalconditions. The three-dimensional network is built up from the corner linkage of newpentameric secondary building units based on two HPO3 pseudo pyramids and threeVO6 octahedra sharing vertices. Compound 15 consists of 3D open-framework withintersecting 12-member ring channels and protoanted template cations residing in thechannels.The first neodymium phosphite 16 has been synthesized. The three-dimensionalnetwork is built up from the corner linkage of NdO8 polyhedron and HPO3 pseudopyramids.A novel three-dimensional transition copper selenite 17 has beenhydrothermally synthesized and characterized by the single-crystal X-ray diffraction.Compound 17 consists of a novel three-dimensional framework constructed fromCuO5 and SeO3 via corner sharing mode.