【作者】 翟丽军；

【导师】 胡拖平；

【作者基本信息】 中北大学 ， 化学工程与技术， 2020， 博士

【摘要】 配位聚合物具有结构易调节、便于功能化等优点,在分子识别、磁学和气体吸附分离等领域有着广阔的应用前景。但配位聚合物的自组装过程受多种因素的影响,因此,具有结构多样性和特定功能配位聚合物的合理设计和构筑既是难点,又是解决限制其应用的关键问题。本论文在溶剂热条件下,基于芳香五羧酸H₅L₁和H₅L₂与过渡金属盐构筑了一系列结构新颖且性能优良的配位聚合物。同时,对这些配位聚合物进行了X-射线单晶衍射、元素分析、红外光谱和热重分析等结构表征。此外,对部分配位聚合物的荧光性质、磁性质和气体吸附性质等进行了研究。具体研究内容及结果如下:（1）基于H₅L₁和H₅L₂与过渡金属离子合成了16个配位聚合物,其化学式如下:{[Zn₅（L₁）₂（μ₃-OH）₂]·2H₃O·2CH₃CN·0.5H₂O}_n（1）,{[Cd₂（L₁）（H₂O）₂]·0.5C₁₀H₁₀N₂·4.75H₂O}_n（2）,{[Co₃（L₁）₂（μ₂-H₂O）₂]·4NH₄·5CH₃CN·3.5H₂O}_n（3）,{[Co_2.75（L₁）（H₂O）_3.5（μ₃-OH）]·1.5NH₄·3CH₃CN·4H₂O}_n（4）,{[Zn₂（L₁）（4,4′-bipy）_0.5（H₂O）]·0.5（4,4′-bipy）·4H₂O}_n（5）,{[Cd₂（HL₁）（1,4-bipb）_0.5（CH₃CN）（H₂O）]·4H₂O}_n（6）,{[Co₃（L₁）（4,4′-biib）（H₂O）（μ₃-OH）]·EtOH·5H₂O}_n（7）,{[Zn₂（HL₁）（1,4-bibb）₂]·5H₂O}_n（8）,{[Zn₅（L₂）₂（H₂O）₅]·3DMA·2.5EtOH·4.5H₂O}_n（9）,{[Cd₅（L₂）₂（H₂O）₆]·DMA·2EtOH·3.5H₂O}_n（10）,{[Co₂（HL₂）（H₂O）₄（μ₂-H₂O）]·3.5H₂O}_n（11）,{[Cu₂（L₂）（1,4-bipb）₂]·H₂N（CH₃）₂}_n（12）,[Co（H₃L₂）（1,4-biib）]_n（13）,{[Ni₅（L₂）₂（1,4-bibb）₂（H₂O）₄（μ₃-OH）₂]·2H₂N（CH₃）₂·3DMA·3H₂O}_n（14）,{[Co₂（HL₂）（4,4′-bibb）₂]·0.5EtOH·2H₂O}_n（15）,{[Cd（HL₂）_0.5（4,4′-bibb）_1.5]·1.5H₂O}_n（16）。X射线单晶衍射分析表明,这些配位聚合物呈现出丰富多变的结构。（2）通过对各个配位聚合物的结构进行比较,发现体系的pH值、金属离子、配体构型等对其结构起着非常重要的作用。在本工作中,通过改变反应体系的pH值构筑了具有不同结构的3D配位聚合物3和4,二者的结构分析表明,体系的pH值影响了配体的配位方式及SBUs的组成,进而导致其结构不同。再如,在金属盐不同的反应条件下,构筑了结构截然不同的配位聚合物15（3D）和16（2D）,这是由于金属离子的配位特性不同所致。此外,对配位聚合物进行了粉末X射线衍射、红外光谱及热重等表征分析,结果显示配位聚合物具有较高的相纯度,并且热稳定性良好。（3）为了揭示配位聚合物的构效关系,对其相关性能进行了研究:（1）对锌和镉配位聚合物的荧光性质进行了研究。结果表明它们对水溶液中Fe³⁺、Hg²⁺、CrO₄^2-和Cr₂O₇^2-等离子具有高灵敏性和选择识别性。此外,通过系列实验探究了荧光淬灭的机理,推测荧光淬灭可能是配位聚合物和检测物之间的竞争吸收和弱作用力共同作用所致。（2）对金属铜、镍和钴基配位聚合物的磁性能进行了测试。直流磁化率的研究结果表明在配位聚合物3、4、7、11、12、13和15中金属离子间存在反铁磁相互作用,而在14中Ni（II）离子间存在铁磁耦合相互作用。通过比较表明所有钴基配位聚合物的χ_MT值均高于其理论值,这可能是由于Co（II）离子的自旋耦合作用所致。此外,交流磁化率数据表明配位聚合物3、4、7、11和15存在频率依赖现象,具有慢迟豫行为,这可能是由于配位聚合物的磁结构具有净磁矩且Co（II）离子具有磁各向异性等原因造成的。（3）对孔隙率较大的配位聚合物进行了N₂、H₂、CO₂和CH₄等气体的吸附性能研究。结果表明这些配位聚合物对N₂、H₂、CO₂的吸附性能优于CH₄。此外,通过理想吸附溶液理论（IAST）模型,模拟分析了配位聚合物对天然气（0.05/0.95）和煤矿坑道气（0.5/0.5）的分离效果,结果表明分离效果良好。最后,利用维里公式（virial-type）计算得气体的吸附热,结果显示一些配位聚合物对CO₂的吸附热较高,表明两者之间具有较强的作用力,进而对CO₂的吸附量也较大。以上结果可能与配位聚合物的孔径大小、气体分子的大小和构型、主客体相互作用力等有关。总之,通过本工作的研究为荧光、磁性、吸附和分离材料的构筑提供了一定的实验基础。此外,性质研究结果表明题目配位聚合物在荧光探针、磁性、气体吸附和分离等方面具有潜在的应用前景,同时,这也为特定功能配位聚合物材料的设计、构筑及其应用提供了重要的指导意义。更多还原

【Abstract】 Coordination polymers have broad application prospects in the fields of molecular recognition,magnetism and gas adsorption and separation due to their advantages of easy structure adjustment and functionalization.However,the self-assembly process of coordi--nation polymers is affected by many factors,therefore,reasonable design and construction of coordination polymers with structural diversity and specific functional is not only a difficult point,but also a key problem that limits their application.In this paper,a series of coordi-nation polymers with novel structures and excellent performance are constructed based on H₅L₁ and H₅L₂ aromatic pentacarboxylic acids and transition metal salts under solvent heat conditions.Meanwhile,the structures of these coordination polymers were characterized by X-ray single crystal diffraction,elemental analysis,IR spectroscopy and thermogravimetric analysis.In addition,the fluorescence properties,magnetic properties and gas adsorption properties of partial coordination polymers were studied.The main research contents and results are as follows:（1）Sixteen coordination polymers were synthesized based on H₅L₁ and H₅L₂ with transition metal ions.Their chemical formulas are listed below:{[Zn₅（L₁）₂（μ₃-OH）₂]·2H₃O·2CH₃CN·0.5H₂O}_n（1）,{[Cd₂（L₁）（H₂O）₂]·0.5C₁₀H₁₀N₂·4.75H₂O}_n（2）,{[Co₃（L₁）₂（μ₂-H₂O）₂]·4NH₄·5CH₃CN·3.5H₂O}_n（3）,{[Co_2.75（L₁）（H₂O）_3.5（μ₃-OH）]·1.5NH₄·3CH₃CN·4H₂O}_n（4）,{[Zn₂（L₁）（4,4′-bipy）_0.5（H₂O）]·0.5（4,4′-bipy）·4H₂O}_n（5）,{[Cd₂（HL₁）（1,4-bipb）_0.5（CH₃CN）（H₂O）]·4H₂O}_n（6）,{[Co₃（L₁）（4,4′-biib）（H₂O）（μ₃-OH）]·EtOH·5H₂O}_n（7）,{[Zn₂（HL₁）（1,4-bibb）₂]·5H₂O}_n（8）,{[Zn₅（L₂）₂（H₂O）₅]·3DMA·2.5EtOH·4.5H₂O}_n（9）,{[Cd₅（L₂）₂（H₂O）₆]·DMA·2EtOH·3.5H₂O}_n（10）,{[Co₂（HL₂）（H₂O）₄（μ₂-H₂O）]·3.5H₂O}_n（11）,{[Cu₂（L₂）（1,4-bipb）₂]·H₂N（CH₃）₂}_n（12）,[Co（H₃L₂）（1,4-biib）]_n（13）,{[Ni₅（L₂）₂（1,4-bibb）₂（H₂O）₄（μ₃-OH）₂]·2H₂N（CH₃）₂·3DMA·3H₂O}_n（14）,{[Co₂（HL₂）（4,4′-bibb）₂]·0.5EtOH·2H₂O}_n（15）,{[Cd（HL₂）_0.5（4,4′-bibb）_1.5]·1.5H₂O}_n（16）。X-ray single crystal diffraction analysis showed that these coordination polymers presented a variety of structures.（2）By comparing the structure of each coordination polymer,it is found that the pH value,metal ions and ligand configuration of the system play a very important role in the structure of coordination polymers.In this work,two 3D coordination polymers 3 and 4 with different structures were constructed by changing the pH value of the reaction system,and the structural analysis of them showed the pH value of the system would affected the coordi--nation mode of ligands and the composition of SBUs,resulting in different structures.For another example,under different reaction conditions of metal salts,coordination polymers15（3D）and 16（2D）with completely different structures were constructed,which was caused by different coordination properties of metal ions.In addition,the coordination polymers were characterized by powder X-ray diffraction,IR spectroscopy and thermogravimetry,and the results showed the coordination polymers had high phase purity and good thermal stability.（3）In order to reveal the relationship between structures and properties of coordination polymers,the related properties were studied as follows:（1）The fluorescence properties of zinc and cadmium coordination polymers were studied.The results showed that they have high sensitivity and selective recognition to Fe³⁺,Hg²⁺,CrO₄^2-and Cr₂O₇^2-ions in aqueous solution.In addition,the fluorescence quenching mechanism was investigated through a series of experiments.and it was speculated that the fluorescence quenching might be caused by the competitive absorption and weak interaction between the coordination polymer and the detector.（2）The magnetic properties of copper-based,nickel-based and cobalt-based coordination polymers were tested.The results of the DC susceptibility study showed that there were anti--ferromagnetic interactions between metal ions in coordination polymers 3,4,7,11,12,13and 15,while there were ferromagnetic coupling interactions between Ni（II）ions in 14.The comparison showed that theχ_MT values of all cobalt-based coordination polymers were higher than the theoretical values,which may be caused by the spin coupling of Co（II）ions.In addition,the AC magnetic susceptibility datas show that coordination polymers 3,4,7,11 and15 have frequency dependence and slow delay of magnetization,which may be caused by the net magnetic moment of the magnetic structure of coordination polymers and the magnetic anisotropy of Co（II）ions.（3）The adsorption properties of N₂,H₂,CO₂ and CH₄ were studied for coordination polymers with high porosity.The results show that the adsorption performance of coordi--nation polymers for N₂,H₂ and CO₂ were better than that of CH₄.In addition,the separation effects of coordination polymers for natural gas（0.05/0.95）and coal mine tunnel gas（0.5/0.5）were simulated and analyzed by the ideal adsorption solution theory（IAST）model and the results showed that the separation effect was good.Finally,The adsorption heat of gas were calculated by using virial formula（virial-type）,and the results showed the adsorption heat of some coordination polymers to CO₂ were higher,indicating that there was a strong force between them and CO₂,and the adsorption amount of CO₂ was also larger.The above results may be related to the pore size of coordination polymer,the size and configuration of gas molecules and the interaction between the host and the object.In a word,the studies of this work can provide a certain experimental basis for the construction of fluorescent,magnetic,adsorption and separation materials.In addition,the properties of the coordination polymers show that they have potential applications in fluorescent probe,magnetic,gas adsorption and separation,and the results also provides important guidance for the design,construction and application of specific functional coordination polymer materials.更多还原