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Hydrothermal Syntheses And Characterization Of Inorganic-Organic Vanadium Selenite Hybrid Materials

Posted on:2005-06-27Degree:DoctorType:Dissertation
Country:ChinaCandidate:Z M DaiFull Text:PDF
GTID:1101360125950150Subject:Inorganic Chemistry
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Recently, the diversity in structures of inorganic-organic hybrid materials hasbeen greatly developed for their potential applications in catalysis, biology andmaterial science. The diversity of the compositions and structures ofinorganic-organic hybrid materials were derived partially from the hugecompositional and structural combinations from individual inorganic and organiccomponents. With the development of zeolite aluminosilicate and metal phosphatewhich constituted the best-known classes of open-framework structures. They werebased entirely upon corner-sharing tetrahedra ([SiO4], [AlO4] etc.). Many of thenewer architectures involve other polyhedra such as octahedral [XO6],pentacoordinated [XO5], pyramidal [XO4] or [XO3] units. These excitingdevelopments will gradually have an impact on the applications of such materials.The traditional applications of aluminosilicate zeolites are in the areas ofion-exchange, separations, and catalysis, but the new generation of materials offers awider range of chemical and physical properties that are only just beginning to be explored. The structures of inorganic solids containing the [SeIVO3]2- selenite ion are veryinteresting because of the nonbonded electron pair that places the cation inasymmetric coordination. From a synthetic and crystal chemical perspective, it issuggested that there is rich structural chemistry in metal selenites. More recently, iABSTRACT Jilin University Ph. D. Thesissome of the novel inorganic-organic hybrid selenites were also reported, such as thefirst inorganic-organic hybrid selenites (CN3H6)4[Zn3(SeO3)5]. As a sequel of serching for new inorganic-organic hybrid selenites, we arecurrently exploring the synthesis of inorganic-organic hybrid vanadium selenites inhydrothermal systems and have synthesized several interesting compounds with thestructures from zero- to three dimensions. We discuss here the syntheses andstructural features of these novel inorganic-organic hybrid vanadium selenites andthe structural relationships among them. Compound 1, {[VO(OH)(H2O)](SeO3)}4·2H2O synthesized using triethylamineas the template, has a 1-D structure constructed from the {[VO(OH)(H2O)](SeO3)}∞chains. Though there are no triethylamine molecules incorporated in the structure,triethylamine is found to be necessary for the formation of 1 since parallel reactionswith different structure-directing agents result in different networks. Two examplesof ethylenediamine-templated vanadium selenite were synthesized: The use ofV2O5/VOSO4 as vanadium sources led to β - (H3NCH2CH2NH3)[(VO)(SeO3)2] (3);In an alternative synthesis, V2O5 was found to be suitable for starting reagents for α -(H3NCH2CH2NH3)·[(VO)(SeO3)2] (2). Compound 2 has a layered structurecomposed of alternating VO5 and SeO3 units with protonated ethylenediamine asinterlayer guest. The framework of 3 consists of macroanionic sheets formed by thenet working of VO6 and SeO3 polyhedra connected through vertices. Layered compound [HN(C6H12)NH]0.5[(VO)(HSeO3)(SeO3)]·H2O (4) containsthe ladder motif consisting of edge-shared four-membered rings, each ring with twoSe and two V atoms. These ladders are connected to one another by HSeO3 group toform a layer. The framework in layered compoud (C4N2H12)0.5[(VO)2(H2O)2(SeO3)2(HSeO3)] (5), is made up of VO6, SeO3 and HSeO3 polyhedra. Alternating VO6 andSeO3 unites formed the four-membered ring chains, which were linked by HSeO3. iiABSTRACT Jilin University Ph. D. Thesis Compounds Co(4,4'-bipy)(H2O)V2Se2O10 6 and Ni(4,4'-bipy)(H2O)V2Se2O10 7,which are structurally analogues, crystallize in the triclinic space group P-1.[M(4,4'-bipy)(H2O)V2Se2O10] (M = Co, Ni) have a t...
Keywords/Search Tags:Inorganic-Organic
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