【作者】 张莉；

【导师】 刘雷；

【作者基本信息】 太原理工大学 ， 化学工程与技术， 2017， 硕士

【摘要】 金属有机膦酸配位聚合物作为一类重要的有机—无机杂化材料,在气体吸附分离、离子交换、催化、质子导体等领域具有潜在的应用价值。与含羧基、含氮基配体相比,有机膦配体在与金属离子结合时可以提供更多结合位点,而且P-C键具有较好的化学稳定性和热稳定性,因而设计合成具有新型结构的金属膦酸盐材料具有重要的意义。到目前为止,大部分的金属膦酸盐材料都是在水热/溶剂热条件下合成的。离子热合成法,利用离子液体或低共熔混合物作为溶剂和模板剂,在制备新型无机多孔材料方面显示出独特的优势。低共熔混合物通常由季铵盐和氢键供体形成,其结构和种类更加丰富、价格低廉,其种类的丰富性以及溶剂性质可调控性为新型金属膦酸盐材料的合成提供了广阔的选择空间。本论文选择了两类低共熔混合物（草酸/季铵盐和尿素/季铵盐）作为反应的介质和潜在的模板剂,对二甲苯二膦酸（H4xbp）作为有机配体与金属Zn/Cu进行配位自组装,系统的研究了这两类低共熔混合物中金属膦酸盐配位聚合物的合成规律及特点。通过调变体系的物化性质和优化合成条件得到了7种新型的金属双膦酸盐化合物,通过单晶数据对其结构进行了解析,并利用粉末XRD、CHN元素分析、IR、TG-DSC、SEM等多种手段对其物化性质进行了系统的表征,主要研究内容和结论包括以下几个方面:1.在草酸/四甲基氯化铵低共熔体系中,系统地研究了添加少量的水和NaOH对反应结果的影响,并合成了四种新型三维结构的二膦酸锌配位聚合物:Zn₂（xbp）（I）,Zn₂（H₂O）₂（xbp）（II）,Na2Zn3（H₂O）₂（xbp）₂（III）,NaZn（H₂xbp）0.5（xbp）0.5·1.5H₂O（IV）。通过单晶衍射数据对其结构进行了解析,四种化合物整体上具有类似性,均是有机配体柱撑的三维骨架结构。其中,化合物III和IV是通过向体系中引入Na+形成的,钠离子分别以NaO4四面体或NaO5六面体的形式存在于无机层中。此外,系统的研究了化合物IV到化合物II的相转变行为,通过XRD、SEM及ICP元素分析等手段揭示了其相转变机理,化合物IV经历了键的断裂,Na+离子解离,Zn₂+离子与配体再组装的过程。2.在草酸/氯化胆碱低共熔体系中,对二甲苯二膦酸四乙酯和二价铜离子反应得到两种二膦酸铜配位聚合物:Cu₂（H₂O）₂（xbp）（V）和化合物VI,其中化合物V和文献中报道的化合物具有类似的骨架结构,发现体系中季铵盐的结构导向作用没有发挥出来。3.在尿素/质子化的有机胺体系中,对二甲苯二膦酸四乙酯和二价锌离子反应得到两种新型的有机膦酸锌材料:未知相化合物VII和化合物（CH₃NH₃）₄Zn₂（xbp）₂·H₂O（VIII）。化合物VII由于单晶尺寸太小,结构待解,但CHN元素分析、FT-IR、TG-DSC实验结果表明该化合物是以尿素原位热分解的无机铵根（NH4+）作为模板剂合成的膦酸锌盐材料。化合物（CH₃NH₃）₄Zn₂（xbp）₂·H₂O（VIII）为新型三维开放骨架结构,膦酸基团具有类羧酸配体的配位特征,甲胺起模板作用并起到平衡骨架电荷的作用。更多还原

【Abstract】 Metal phosphonates as significant organic-inorganic hybrid materials have been extensively pursued as gas adsorption separation,ion-exchange materials,catalysts,proton conductors and so forth.Phosphonate group can provide more modes of coordination and myriad different arrangements that structures can take,then forming stronger bonds compared with most compounds based on the carboxylic acid ligand,that is of significance to design and prepare metal phosphonates with rich structures and high thermal stability.Most of metalphosphonates,to date,were synthesized by using hydro/solvothermal method,and the solvent used are often crucial to final structures.Ionothermal synthesis has been developed by using ionic liquids or deep eutectic solvents as the solvents and potential templates,showing unique advantages to prepare novel inorganic porous crystalline solids.Deep eutectic mixtures are generally composed of quaternary ammonium salts and hydrogen-bond donors,its species and structure are very rich and dynamic and its price is lower.Ionic liquids with rich species and disignable properties provide a new approach to synthesize novel metal phosphonates.In this paper,two deep eutectic mixtures（oxalic acid/quaternary ammonium salts and urea/quaternary ammonium salts）were selected as the solvent and source of template or the structure-directing agent,the p-xylylenebisphosphonate ligands（H4xbp）as the ligand coordinated with metals zinc or copper.As a result,seven novel crystalline metal diphosphonates were successfully ionothermally synthesized by adjusting the physical and chemical properties of the system and optimizing the synthetic conditions,and their structures were determined by single-crystal diffraction data.Powder XRD,CHN element analysis,FT-IR,TG-DSC and SEM were also illustrated characterize these samples.The main contents and conclusions are as follows:1.In the deep eutectic solvent of oxalic acid and tetramethylammonium chloride,the effect of adding a small amount of water and NaOH on the reaction results was systematically studied,and four novel crystalline zinc diphosphonates,Zn₂（xbp）（I）,Zn₂（H₂O）₂（xbp）（II）,Na2Zn3（H₂O）₂（xbp）₂（III）and NaZn（H₂xbp）0.5（xbp）0.5·1.5H₂O（IV）were ionothermally synthesized from tetraethyl-p-xylylenebisphosphonate（Texbp）and Zn（OAc）₂.They had a similar characteristic of inorganic layers pillared by organic parts of ligands on the whole.The introduction of sodium ions led to two Na-containing zinc diphosphonates（III and IV）,wherein the sodium ions adopt in NaO4 tetrahedra or NaO5 distorted hexahedra in the inorganic layers.Moreover,the phase transition behavior of compound IV to compound II was systematically studied.Powder XRD patterns and SEM images of the isolated samples were collected to detect the phase-transformation process,and the concentration change of Na+ ions in solution with different soaking time was measured by ICP method.The phase-transition behavior from compound IV to II occurs after soaking in water at room temperature,experiencing the process of bond cleavage,Na+ ions dissociation,and self-assembly between Zn₂+ ions and ligands.2.The compound Cu₂（H₂O）₂（xbp）（V）and an unknown compound VI were obtained from tetraethyl-p-xylylenebisphosphonate（Texbp）and Cu₂₊ in the deep eutectic solvent of oxalic acid/choline chloride.The compound Cu₂（H₂O）₂（xbp）（V）has similar three-dimensional structure to the reported compound in the literature.However,the template or structure-directing role of the quaternary ammonium salt cation did not play in the final structures.3.In the deep eutectic solvent of urea/protonated organic amines,two novel crystalline zinc diphosphonates-compound VII and compound（CH₃NH₃）₄Zn₂（xbp）₂·H₂O（VIII）were obtained from tetraethyl-p-xylylenebis phosphonate（Texbp）and Zn₂+.Because the size of the compound VII is too small,its structure is to be solved.But the results of CHN elemental analysis,IR and TG-DSC analysis showed that NH4+ derived from urea as the structure-directing agent.The compound（CH₃NH₃）₄Zn₂（xbp）₂·H₂O（VIII）have a special three dimensional open framework with rhombic channels.It is found that reducing the coordination number of the phosphonate group just like dicarboxylate linkers in MOFs.The organic cations [CH₃NH₃]+ played a structure-directing role and make the compound being neutral and stabilize framework structure.更多还原