Hydrothermal Synthesis And Structural Characterization Of Hybrid Crystal Compounds In Vanadium Systems

Many remarkable natural materials are formed by the co-existence of inorganic components and organic molecules. They can possess unique and specific properties, such as catalytic activity, biology activity, piezoelectricity and ferromagnetism. Besides, it is found that organic molecules can dramatically influence the microstructures of inorganic components. Based on the above founding, we aim to design novel functional materials with novel structures and unique properties according to mimic nature's use of organic molecules to modify inorganic microstructures. In the design of this kind of hybrid materials, organic molecules can influence the nucleation and growth of inorganic compound, and control the microstructure of the inorganic framework. By the interaction of the interface between the organic molecules and inorganic components, the organic molecules can imprint the structure information to the inorganic framework and thus obtain a series of hybrid materials with novel structures and special properties. Recently, the various in structures of inorganic-organic hybrid materials has been greatly developed for their potential applications in catalysis, biology and material science. The diversity of the compositions and structures of inorganic-organic hybrid materials were derived partially from the huge compositional and structural combinational from individual inorganic and organic components. Taking into account the international studies, we have focused our study on the synthesis of inorganic-organic hybrid compounds with novel structures and the influence of the changes caused by the coordination position or conformation of organic component on the structure of inorganic-organic hybrid compound. We discuss here the syntheses and structural features of these novel inorganic-organic hybrid compounds in the vanadium system and the structural relationships among them. During the course of preparing new hybrid compounds in V-O system, four new compounds (compounds 1-4) have been synthesized hydrothermally using organic molecules as structure-directing agents or ligands. The characteristic basic building unit in the structure of compound 1 is a distorted sodalite cage, which contains corner-sharing VO4 tetrahedrons and CoO6 octahedra as well as the C2O4 group. Compound 2 is consist of layered mixed-valence vanadium oxides with interlayers {Ni(en)2}2+. In the structure of 2, a novel arrangement of vanadium and oxygen atoms of {V3O7}-was found different from that in its isomer [Zn(en)2][V6O14]. The structure of compound 3 is an one-dimensional cobalt vanadate chain, constructed from 1D [V3O9] helical chain and covalently attached [Co(2,2'-bipy)2]3+ fragments. The structure of compound 4 is a two-dimensional cobalt vanadate layer, consisted of an anionic [V8O23]n3n-chain with [Co(1,10'-phen)2]3+ moieties covalently bonded to the vanadium oxide chain. During the course of preparing new hybrid compounds in V-As-O system, nine new compounds (compounds 5-13) have been synthesized hydrothermally using organic molecules as ligands. Compound 5 is composed of discrete [(VO2)2(HAsO4)] 3-membered rings bonded to two 2,2'-bpy ligands. Compound 6 contains an unusual 1D ladder-like {V/As/O} chain with the 2,2-bpy ligands directly coordinated to the vanadium arsenate skeleton. Compound 7 contains an unusual 1D tubular {V/As/O} chain with the 2,2-bpy ligands directly coordinated to the vanadium arsenate skeleton. The compound 8 exhibits a 2D arsenic vanadate network decorated with 2,2'-bpy ligands. Compounds 9, 10 contain two arsenic vanadate chains linked through [Cu(2,2'-bpy)]2+ or [Cu(1,10-phen)]2+complexes. The structure of compound 11 is a two-dimensional layer, consisted of an anionic one-dimensional arsenic vanadate chain [(VO2)2(AsO4)]n2n-with [Cu(2,2'-bpy)]2+ moieties covalently bonded to the chain. The structure of compound 12 is a three-dimensional copper vanadate open framework, constructed from 1D [CuV3O7(AsO4)] double helical chain linked by 4,4'-bpy organic bridged molecules. Compound 13 has a novel 3D structure constructed from two subunits, e.g., [(VO2)(HAsO4)]∞helical chains and[Co(4,4'-bpy)2]2+ fragments. These helical chains are composed of alternatively corner-sharing HAsO4 tetrahedra and VO4N trigonal-bipyramids. 4,4'-bpy molecular acts as a bifunctional organic ligand, directly linking Co and V atoms in the As-V-O chains. The formation of the helix in the structure may be partially due to the introduction of an extra-force from the [Co(4,4'-bpy)2] fragment. The interaction of [Co(4,4'-bpy)2] fragment with each vanadium atom on the helical chains may be very important for stabilizing the helix. During the course of preparing new compounds in M-I-O system, six new compounds (compounds 14-19) have been synthesized. The structure of compound 14 consists of infinite two-dimensional layers with Li+ arranged between the layers. The layer of 14 constructed from left-handed helical and right-handed helical chains units. The structure of compound 15 consists of infinite one-dimensional chains with Na+ arranged between the chains. The main body of the chain is left-handed helical. The structure of compound 16 consists of infinite one-dimensional chains with K+ arranged between the chains. Compound 17 is composed of discrete [Cu(H2O)(IO3)2] 3-nucleus clusters bonded to one 2,2'-bpy ligand. Compound 18 contains an unusual 1D ribbon-like {Cu/I/O} chain with the 2,2-bpy ligands directly coordinated to the copper iodate skeleton. Compound 19 can be described as folded copper-iodine oxide ribbons decorated with 2,2'-bipy ligands extending sideways from four faces of the inorganic chain. A remarkable feature of compound 19 is the presence of potential large sized channels. The total and accessible void volumes of both types of channels are estimated to be about 44% and 18% of the volume of the unit cell, respectively. The surface enclosing the void volume is about 3073.14 ?2/u.c. We tried to synthesize new materials in M-I system by new method, and got four new compounds (compounds 20-23). Compound 20 is composed of discrete [CuI] 1-nucleus cluster bonded to two 2,2'-bpy ligands. Compound 21 is composed of discrete [Cu2I2] 2-nucleus clusters bonded to two 2,2'-bpy ligands. Single crystal X-ray diffraction analysis of 22 and 23 reveals the formation of 1-D ribbon-like structure. A remarkable feature in compound 22 and 23 is the presence of hexanuclear Cu6I6 cores. The hexanuclear Cu6I6 core is constructed by the combining of two boat-shaped trinuclear Cu3I3 cores via six I anions. The structure of the hexanuclear Cu6I6 cores is similar to the double six-membered rings (D6R) found in...