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Syntheses,Structures And Fluorescence Properties Of Rare-Earth/Heterometal Incorporated Tellurotungstate Aggregates

Posted on:2018-02-28Degree:MasterType:Thesis
Country:ChinaCandidate:Q HanFull Text:PDF
GTID:2321330518463614Subject:Chemistry, physical chemistry
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In this dissertation,based on the one-step self-assembly reaction,the simple materials Na2WO4·2H2O and K2TeO3 with lone pair of electrons are used as the starting reaction materials to construct different lacunary tellurotungstate fragments by controlling the molar ratio of reactants and the pH of the solution,and then metal ions and organic ligands are introduced to the reaction system to synthesize organic–inorganic hybrid rare-earth?RE?,transition-metal?TM?–RE heterometal and main-group–RE heterometal incorporated tellurotungstate aggregates.Thus,nineteen novel tellurotungstate aggregates containing[B-?-Te W9O33]8–,[B-?-TeW8O31]8–and[B-?-TeW8O31]8–building units have been successfully synthesized,and characterized by elemental analyses,infrared spectra and X-ray single-crystal diffraction.The thermogravimtric behaviors,fluorescence and magnetic properties of some related compounds have been studied.This dissertation will be divided into four parts to expand my work during the course of my master degree:Part I.A series of organic–inorganic hybrid RE-incorporated tellurotungstates Na2H12[La2?H2O?4?pica?2W2O6][?La?H2O?W2?Hpica?2O4?(TeW8O30)2]2·12H2O?1?,Na2H12[Ce2?H2O?4?pica?2W2O6][?Ce?H2O?W2?Hpica?2O4?(TeW8O30)2]2·12H2O?2?,Na2H12[Nd2?H2O?4?pica?2W2O6][?Nd?H2O?W2?Hpica?2O4?(TeW8O30)2]2·12H2O?3?,Na2H12[Sm2?H2O?4?pica?2W2O6][?Sm?H2O?W2?Hpica?2O4?(TeW8O30)2]2·12H2O?4?and Na2H12[Eu2?H2O?4?pica?2W2O6][?Eu?H2O?W2?Hpica?2O4?(TeW8O30)2]2·12H2O?5?were obtained via the one-pot assembly reaction of Na2WO4·2H2O,RE?NO3?3·6H2O,K2TeO3 and Hpica in the conventional aqueous solution.Single-crystal X-ray diffraction indicates that the tetrameric polyoxoanions of 1-5 are constructed from two sandwich-type{?RE?H2O?W2?Hpica?2O4?(B-?-TeW8O30)2}9-building blocks linked by one RE-W-O hybrid cluster{RE2?H2O?4?pica?2W2O6}4+.The sandwich-type{?RE?H2O?W2?Hpica?2O4?(B-?-Te W8O30)2}9-building block is constituted by two tetravacant Keggin-type fragments[B-?-TeW8O30]8-anchoring the other RE-W-O hybrid cluster{?RE?H2O?W2?Hpica?2O4?}7+.The thermal decomposition procedures of 2 and3 have been profoundly studied by variable-temperature IR spectra and variable-temperature PXRD patterns.Moreover,the photoluminescence properties of 3–5 have been also investigated and their emission spectra show the characteristic emission bands attributable to the RE f–f electron transitions.Part II.On the basis of the first part of work,in order to construct more complicated organic-inorganic hybrid RE-substituted tellurotungstate aggregates,we introduced the flexible citric acid into the reaction system and successfully obtanined four citrate-bridging RE substituted tellurotungstate aggregates[H2N?CH3?2]6H10[La12?H2O?34?ca?4W12O28][B-?-TeW9O33]8·32H2O?6?,[H2N?CH3?2]6H10[Ce12?H2O?34?ca?4W12O28][B-?-TeW9O33]8·32H2O?7?,[H2N?CH3?2]6H10[Pr12?H2O?34?ca?4W12O28][B-?-TeW9O33]8·32H2O?8?and[H2N?CH3?2]6H10[Nd12?H2O?34?ca?4W12O28][B-?-TeW9O33]8·32H2O?9?.The octameric polyoxoanions of 6-9are constructed from two tetrameric[RE6?H2O?17?ca?2W6O14][B-?-TeW9O33]48-fragments connected by two RE3+ions and two carboxylic oxygen atoms of citrate ligands.This citrate-bridging high-nuclear RE3+clusters are very rare in polyoxometalate chemistry.In addition,the solid-sate near-infrared photoluminescence properties of 9 have been carried out at ambient temperature.The near-infrared emission spectrum of 9 exhibits the characteristic emission bands derived from Nd3+centers and the luminescent decay curve is fitted to a double exponential function.Part III.A series of organotin–RE heterometal incorporated tellurotungstate hybrids H18Na2{[Sn?CH3?W2O4?INA?][B-?-TeW8O31Ce?H2O??Ac?]2}2·12H2O?10?,H18Na2{[Sn?CH3?W2O4?INA?][B-?-TeW8O31Pr?H2O??Ac?]2}2·12H2O?11?,H18Na2{[Sn?CH3?W2O4?INA?][B-?-TeW8O31Nd?H2O??Ac?]2}2·12H2O?12?,H18Na2{[Sn?CH3?W2O4?INA?][B-?-TeW8O31Sm?H2O??Ac?]2}2·12H2O?13?,H18Na2{[Sn?CH3?W2O4?INA?][B-?-TeW8O31Eu?H2O??Ac?]2}2·12H2O?14?,H18Na2{[Sn?CH3?W2O4?INA?][B-?-TeW8O31Gd?H2O??Ac?]2}2·12H2O?15?and H18Na2{[Sn?CH3?W2O4?INA?][B-?-TeW8O31Tb?H2O??Ac?]2}2·12H2O?16?were synthesized by introducing orgaotin group and RE ions into the reaction system.The tetrameric polyoxoanions of 10–16 are built by two symmetrical units{[Sn?CH3??IN?][(B-?-TeW8O31)Nd?H2O??Ac?]2}10–linked by acetate connectors.10–16 represent the first inorganic–organic hybrid RE-substituted tellurotungstates involving three different organic ligands and the first organotin–RE heterometallic polyoxometalate derivatives.The solid-state luminescent emission spectra of12–14 mainly display the charcteristic emission bands of RE caitons whereas the luminescent emission behavior of 16 is accomplished by the combined actions of Tb3+ions and tellurotungstate polyanions.Furthermore,the 13@CTAB composites with peanut-like and honeycombed morphologies were prepared by a surfactant cetyltrimethylammonium bromide?CTAB?.The time-resolved emission spectra of 13@CTAB consolidate the energy transfer from CTAB to RE3+centers.Part IV.By introducing Co2+and RE3+ions into the reaction system,a series of novel Co–RE heterometallic tellurotungstate derivatives[H2N?CH3?2]8Na4H10[Co?H2O?3]2[Co W10Te2O34][Dy(B-?-TeW8O31)]2[(Dy?H2O?3(B-?-TeW8O31)]2·24H2O?17?,[H2N?CH3?2]8Na4H10[Co?H2O?3]2[CoW10Te2O34][Ho(B-?-TeW8O31)]2[(Ho?H2O?3(B-?-TeW8O31)]2·24H2O?18?and[H2N?CH3?2]8Na4H10[Co?H2O?3]2[CoW10Te2O34][Er(B-?-TeW8O31)]2[(Er?H2O?3(B-?-TeW8O31)]2·24H2O?19?were obtained.To the best of our knowledge,17–19 represent the first TM–RE heterometallic tellurotungstate derivatives comprising three different types of[B-?-Te W8O31]8-,[B-?-TeW8O31]8-and[CoW10O44]8-units.Morover,their infrared spectra have been measured.
Keywords/Search Tags:tellurotungstate, heterometallic hybrid material, composite material, fluorescence property
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