【作者】 张春丹；

【导师】 刘术侠； 苏忠民；

【作者基本信息】 东北师范大学 ， 物理化学， 2010， 博士

【摘要】 本论文利用缺位的Dawson型磷钨酸盐簇为反应前躯体,通过与过渡金属、主族金属和金属有机配合物反应生成新型的多金属氧酸盐化合物,研究这类化合物的合成条件及规律,以及新物质的结构与性能间的关系。利用水热合成与常规水溶液合成方法,合成了几种新型的多金属氧酸盐化合物,通过元素分析,IR,TG, EPR,NMR和单晶X-射线衍射对晶体结构进行了表征,对化合物的热稳定性,磁学性质和电化学性质进行了初步研究。1、六缺位的K₁₂[H₂P₂W₁₂O₄₈]·24H₂O与过渡金属在水溶液中反应生成的赤道位三铁取代的化合物及其性质: K₄Cs₂Fe₂[P₂W₁₅（FeOH）₃O₅₉]·22H₂O （1）这个化合物的显著的结构特点是三个Fe取代的位置不同于经典的极位三取代的化合物,而是取代了Dawson型磷钨酸盐阴离子簇赤道位的三个W的位置。利用X-ray、TG、IR、变温磁化率研究、电化学等表征了化合物的结构、稳定性、磁性,电化学及电催化性质。磁学性质研究表明化合物1的三个取代的FeIII之间显示了强的反铁磁性相互作用,磁性结果的拟合也证明了这一点。由于化合物1不溶于水和一般的有机溶剂,以化合物1为修饰剂的本体修饰碳糊电极（1-CPE）被用来研究它的电化学性质和对亚硝酸盐和抗坏血酸的电催化活性。2、缺位的Dawson型磷钨酸盐与主族金属在水溶液中反应生成的化合物及其性质: K₁₀[H₆{P₂W₁₃O₅₁}₂Sb₄]·21H₂O （2） [（CH₃）₂NH₂]₅[H₂{P₂W₁₇SbO₆₁}]·18H₂O （3）化合物2代表了第一个以主族元素为夹心原子的Dawson型道赤位夹心化合物。与同主族四面体配位的P （V）和As （V）不同,由于Sb （III）的孤电子对的空间效应导致了三角锥的配位几何构型,并在分子中心含有一个立方的空笼。该化合物的成功的合成和结构的表征为缺位的Dawson多阴离子与主族金属元素的反应提供了一个吸引人的模型。化合物3是Sb（III）单取代的Dawson型磷钨酸盐,由于Sb（III）的孤电子对效应而显示了特殊的四配位模式。利用X-ray、TG、IR、UV-vis、NMR、电化学等表征了化合物的结构、稳定性、电化学及电催化性质。UV-vis和³¹P NMR证明了2在水溶液中的稳定性。化合物2溶于0.5 M CH₃COOK + CH₃COOH缓冲溶液中的电化学研究表明其对NO2-的还原具有很好的电催化活性3、以缺位的Dawson型多阴离子为反应前躯体,水热条件下合成具有高核磁簇的化合物及其性质（Phen = 1, 10-phenanthroline, bdc =1,4-benzenedicarboxylate）: [Cu₂（Phen）₄Cl][Cu₂（Phen）₃（H₂O）Cl][P₂W₁₈O₆₂]·H₂O （4） [Cu₇（Phen）₇（H₂O）4Cl₈][P₂W₁₈O₆₂]·6H₂O （5） K₂[{（CuPhen）₂Cl₂}₂（bdc）]2[P₂W₁₈O₆₂]·6H₂O （6）使用不同的多金属氧酸盐前驱体和Cu-phen复合物在水热条件下合成出三个基于[P₂W₁₈O₆₂]^6-多阴离子簇的无机-有机杂化化合物。在这几个化合物中通过Cl和对苯二甲酸（bdc）配体桥连不同的Cu-phen复合物片段组合成了新的具有不同核性的Cu-phen复合物。在化合物4与5中,由于Cu-Cl-Cu键角分别接近180o和90o而导致了它们的CuII之间分别显示了反铁磁性和铁磁性相互作用。在化合物6中通过Cl和bdc桥的连接不同的Cu-phen复合物片段组合成了新的四核的Cu-phen复合物,该化合物的磁行为显示了反铁磁性和铁磁性相互作用的混合。它们的高热稳定性、在不同溶剂中的低溶解性及富含多金属氧酸盐的特性使它们有可能成为理想的电催化材料。电化学研究表明5和6对于亚硝酸盐的还原具有很好的电催化活性。这个工作表明反应原料、阴阳离子的尺寸和反应物比例的适当结合在水热条件下能够形成具有不同的结构和功能的新型材料。4、以缺位的Dawson型多阴离子为反应前躯体,水热条件下合成一维链状化合物及其性质（bpy = bipyridine）: （4,4’-H₂bpy）₄[{Cu（4,4’-Hbpy）₂（4,4’-bpy）}{P₂W₁₈O₆₂}]·7H₂O （7） [Cu（2,2’-bpy）]₂ [H₂P₂W₁₈O₆₂]·8H₂O （8）在水热条件下合成出两个基于[P₂W₁₈O₆₂]^6-多阴离子簇的无机-有机杂化物。化合物7是由过渡金属配位聚合物链{Cu（4,4’-Hbpy）2（4,4’-bpy）}_nⁿ⁺和多金属氧酸盐簇[P₂W₁₈O₆₂]^6-连接形成的一维链状化合物。而化合8则是由两个[Cu（2,2’-bpy）₂]复合物片段与[H₂P₂W₁₈O₆₂]^4-交替连接形成的一维链状化合物。更多还原

【Abstract】 Our work is focused on the design and preparation of new polyoxometalate compounds based on the lacunary Dawson type tungstophosphates which react to various metal compounds or metal-organic complexes. The study on sythetic conditions and rules for these new copounds and the exploration of relationships between structures and properties for these new compounds are also carried out.Several new polyoxometalate compounds have been synthesized on the basis of water solution synthesis methods or hydrothermal technique and structurally characterized by elemental analyses, IR,TG, EPR,UV-vis,NMR and single crystal X-ray diffractions. The thermal stabilities, magnetic properties and electrochemical behavior of these compounds have been studied.1. Interaction of the hexa-lacunary polyanion precursor [α-H₂P₂W₁₂O₄₈]12- with the FeIII in aqueous solution results in the formation of an equatorial tri-iron substituted Wells-Dawson type compound: K₄Cs₂Fe₂[P₂W₁₅（FeOH）₃O₅₉]·22H₂O （1）Compound 1 was characterized by IR, elemental, single-crystal X-ray diffraction, thermogravimetric, magnetic, as well as electrochemical analyses. The [P2W15（FeOH）3O59]12- polyoxoanion can be viewed as a derivative of parent [α-P₂W₁₈O₆₂]6- polyoxoanion by removal of three belt W=O groups and then inhabited by three Fe=OH groups. The compound 1-modified carbon paste electrode （1-CPE） presents good electrocataltic activity not only toward the reduction of nitrite, which is attributed to the function of tungstophosphate, but also toward the oxidation of ascorbic acid, which is primarily attributed to the function of FeIII. The magnetic properties of 1 have been studied by magnetic susceptibility and magnetization measurement and fitted according to an isotropic exchange model. 1 exhibits strong antiferromagnetic spin exchange interactions between the FeIII centers.2. Interaction of the lacunary lacunary Dawson type tungstophosphate precursors with main group metal elements in aqueous solution results in the formation of new Wells-Dawson type polyanions clusters: K₁₀[H₆{P₂W₁₃O₅₁}₂Sb₄]·21H₂O （2） [（CH₃）2NH₂]5[H₂{P₂W₁₇SbO₆₁}]·18H₂O （3）A sandwich-type anionic cluster of a new lacunary building block [P2W13O51]14- has been prepared: 2 was synthesized in one-pot self-assembly reaction of [H₂P₂W₁₂O₄₈]12- with C₄H₄KO₇Sb·0.5H₂O. The compound 3 is an antimony（III） substituted Wells-Dawson type tungdstophosphate. They have been characterized by single-crystal X-ray analysis, IR, thermogravimetric analysis, elemental analysis, UV, NMR and electrochemistry. 2 represents the first dimetric, antimony-containing polyoxoanion derived from vacant Dawson-type tungstophosphate. In contrast to the tetrahedrally coordinated P （V） and As （V） of the same main group, Sb （III） give new structural information because of the stereochemical effect of the lone pair electrons located on top of the trigonal pyramid. Examination of cyclic voltammograms displays a good electrocatalytic activity toward the reduction of nitrite. The polyanion 2 is stable in solution, as shown by UV spectra and 31P NMR spectroscopy. Due to the excellent stability of 2, it is promising to use 2 as a new polyoxometalate precursor to research its extensional structures.3. Interaction of the lacunary lacunary Dawson type tungstophosphate precursors with metal-organic complexes in hydrothermal condition results in the formation of new hybrid compounds with multinuclear magnetic clusters（Phen = 1, 10-phenanthroline, bdc = 1,4-benzenedicarboxylate）: [Cu₂（Phen）₄Cl][Cu₂（Phen）₃（H₂O）Cl][P₂W₁₈O₆₂]·H₂O （4） [Cu₇（Phen）₇（H₂O）4Cl₈][P₂W₁₈O₆₂]·6H₂O （5） K₂[{（CuPhen）₂Cl₂}₂（bdc）]2[P₂W₁₈O₆₂]·6H₂O （6）Three novel hybrid compounds containing multinuclear CuII complex cations, have been obtained in hydrothermal conditions and characterized by IR, elemental, thermogravimetric, magnetic, electrochemical and single-crystal X-ray diffraction analyses. The main structural feature to these compounds is the presence in different copper-Phen complex moieties which compose new multinuclear copper-Phen complexes linked by Cl and bdc ligands. The Cu-Cl-Cu angles of binuclear and heptanuclear copper-Phen complexes are close to 180o and 90o, respectively. This difference induces that 3 and 4 exhibit antiferromagnetic and ferromagnetic spin exchange interactions between the CuII centers, respectively. The magnetic behavior of 5 is unusual and interesting, indicative of a strong antiferromagnetic interaction admixture with a ferromagnetic interaction. The 4-CPE and 4-CPE display good electrocatalytic activity toward the reduction of nitrite. This work reveals that appropriate combination of materials, size and ratio of anion and cation, and hydrothermal synthetic conditions can lead to the formation of POM-based complexes with different structural and functional characteristics.4. Interaction of the lacunary lacunary Dawson type tungstophosphate precursors with metal-organic complexes in hydrothermal condition results in the formation of new 1D chain hybrid compounds（bpy = bipyridine）: （4,4’-H₂bpy）₄[{Cu（4,4’-Hbpy）₂（4,4’-bpy）}{P₂W₁₈O₆₂}]·7H₂O （7） [Cu（2,2’-bpy）]₂ [H₂P₂W₁₈O₆₂]·8H₂O （8）Two new 1D chain hybrid compounds have been obtained in hydrothermal conditions. Compounds 7 is constructed by {Cu（4,4’-Hbpy）2（4,4’-bpy）}_nⁿ⁺ chain and Dawson type polyanion cluster [P₂W₁₈O₆₂]^6-. Compound 8 show one-dimensional chain formed by two[Cu（2,2’-bpy）₂]²⁺ and [H₂P₂W₁₈O₆₂]^4-.更多还原