【作者】 刘畅；

【导师】 马建方；

【作者基本信息】 东北师范大学 ， 无机化学， 2022， 博士

【摘要】 食品和药物安全以及环境污染是关系到人类健康和生态可持续发展的两大重要问题。在食品、医疗和环境等领域实现食品有害物、药物和环境污染物的灵敏、准确和高效的检测是十分重要的。相比传统的检测方法,电化学检测方法凭借响应快、成本低、灵敏度高和设备易于微型化等优势激发了研究者们的研究热情。电化学检测方法主要依靠传感元件完成,而在构建传感元件的过程中,电极表面修饰材料的选择很大程度上决定了传感器分析性能的上限。因此,发展新型的电极材料是提升电化学传感器分析性能的关键。金属-杯[4]芳烃配合物凭借其多孔结构、催化活性以及荧光特性已被应用于气体储存和分离、有机催化以及荧光检测等多方面,而对其电化学性能方面的研究较少。为了探究其在电化学传感领域的应用潜能,在本论文中合成了五种金属-杯[4]芳烃配合物并制备成不同的电化学传感器分别用于快速且准确地检测黄酮类药物、双酚类分子和重金属离子。主要研究内容及结果包括:1.基于对叔丁基硫代杯[4]芳烃（H₄TC4A）,合成了一种哑铃形的杯[4]芳烃配合物[Co₄（TC4A）₂]·3DMF·Me OH（Co-TC4A）。进一步,在溶剂热反应中利用介孔碳（OMC）作为支撑平台原位生长Co-TC4A,制备了两者的复合材料（Co-TC4A@OMC（1:1））。Co-TC4A和OMC之间的协同效应显著地提高了Co-TC4A的催化效率、电导率和比表面积等性能。利用该复合材料修饰的玻碳电极（Co-TC4A@OMC（1:1）/GCE）作为检测黄芩素的电化学传感器在实际检测中表现出较强的吸附能力和优异的电催化活性,检测结果具有较宽的线性范围（0.005–17.00μM）、较高的灵敏度(8.96μAμM^-1)和极低的检出限（1.6 n M）。此外,该传感器还可以用于实际药品黄芩素铝胶囊中黄芩素的检测,取得了令人满意的回收率。2.基于前一章的研究基础,以H₄TC4A为母体,利用咪唑基团修饰杯芳烃的下缘并将连接苯环的硫桥氧化,得到被四个咪唑基团功能化的砜桥杯[4]芳烃配体（L¹）。利用L¹、间苯二甲酸（H₂IPA）和Zn（Ⅱ）阳离子合成了具有丰富孔道结构的2D MOF[Zn₂（L）（IPA）（H₂O）]·2DMF·2Me OH·3H₂O（Zn-L-IPA）。由于在溶剂热反应过程中引入了盐酸,导致L¹发生部分C–O键断裂并转化为配体（H₂L）。利用该MOF材料复合高电导性的石墨粉（GP）,结合主-客体识别策略和电化学检测方法,开发了一种快速、高选择性且超灵敏的双酚类化合物电化学传感平台（Zn-L-IPA@GP/GCE）。在电化学检测前的预富集阶段,Zn-L-IPA@GP特定尺寸和结构的1D孔道对三种结构相似的双酚类化合物表现出不同的吸附能力。因此,对双酚F（BPF）和双酚A（BPA）的检测结果表现出较宽的线性范围,分别为0.005–10.50μM和0.01–8.50μM,以及极低的检出限,分别为0.2和3.5 n M,而对双酚S（BPS）几乎没有电化学响应。密度泛函理论（DFT）计算结果表明,氢键和π-堆积作用可能是Zn-L-IPA宿主与双酚分子客体之间存在的主要相互作用。客体分子的体积、偶极矩、电子结构和几何形状等多种因素会影响主体空腔对客体分子的选择性吸附。3.进一步利用H₄TC4A,改变溶剂热条件,分别合成了哑铃形的四核Bi簇[Bi₄（TC4A）₂（μ₄-O）]·2NO₃·3DMF·3Me OH（Bi₄-TC4A）和不规则球形的八核Bi簇[Bi₈（TC4A）₅（en）₂（μ₃-OH）₂（μ₄-OH）₂]·5DMF·2Me OH（Bi₈-TC4A）。发挥Bi基材料和杯芳烃配体在检测重金属离子方面的独特优势,将两种铋簇配合物修饰在玻碳电极上分别制备成工作电极（Bi₄-TC4A/GCE和Bi₈-TC4A/GCE）,用于检测水溶液中的Cd²⁺和Pb²⁺。其中,Bi₈-TC4A/GCE对两种重金属离子的传感性能更佳,对Cd²⁺和Pb²⁺检测的灵敏度分别为12.71和18.14μAμM^-1,检出限分别为12.4和8.2 n M。4.利用4-巯基吡啶修饰的间苯二酚杯[4]芳烃（TMC4R）为主配体,引入对苯二甲酸（1,4-H₂BDC）为辅助配体,设计了一种新型含硫的纳米胶囊形MOF[Co₂（TMC4R）（1,4-BDC）₂（μ₂-H₂O）]·3DMF·CH₃OH·5CH₃CN·H₂O（Co-TMC4R-BDC）。将该MOF直接用作电极修饰材料,成功制备了电化学传感平台（Co-TMC4R-BDC/GCE）,并详细地评价了该传感平台对四种HMIs(Pb²⁺、Cu²⁺、Cd²⁺和Hg²⁺)的电化学检测性能。由于Co-TMC4R-BDC有均匀分布的硫原子、特殊的空腔结构以及可接受的导电性,因此,基于该MOF构建的HMIs传感平台表现出很好的电化学传感行为,特别是对Cd²⁺、Pb²⁺和Cu²⁺的最低检出限分别达到了26.4、11.2和13.3 n M,该检测限远低于世界卫生组织推荐的饮用水水质标准值。此外,Co-TMC4R-BDC/GCE电极还表现出良好的重现性、稳定性、选择性以及对实际水样的检测能力。根据XPS结果,我们合理地推断,该MOF传感器潜在的捕获机制是利用晶体结构中的硫原子与HMIs配位达到捕获水溶液中更多金属离子的目的,从而在下一步的检测过程中提高检测的灵敏度。另外,DFT计算还证明了间苯二酚杯[4]芳烃的四个苯环可以通过阳离子-π作用与金属离子结合,也可以有效地促进HMIs的捕获和检测。本工作采用了协同促进策略,通过设计含硫和碗状空腔的纳米胶囊形MOF制备HMIs电化学传感平台,实现了对多种HMIs的捕获和超灵敏检测。更多还原

【Abstract】 Food and drug safety as well as environmental pollution are two important issues related to human health and ecological sustainable development.It is an urgent and challenging task to achieve sensitive,accurate and efficient detection of drugs and contaminants in medical,food and environmental fields.Compared with traditional detection methods,electrochemical detection methods have exerted a tremendous fascination on researchers’attention because of their outstanding advantages such as fast response,low cost,high sensitivity and miniaturization of instruments.In the development of electrochemical sensors,modified materials play the crucial role in the improvement of detection performances.Therefore,the synthesis of functional and more environmentally friendly sensing materials is the key factor for electrochemical sensing.Metal-calix[4]arene complexes have potential applications in gas storage and separation,organic catalysis and fluorescence detection due to their porous structure,catalytic activity and fluorescence characteristics,but their electrochemical properties are rarely studied.In order to explore their potential application in the field of electrochemical sensing,five metal-calix[4]arene complexes were synthesized,and different electrochemical sensors were prepared for rapid and accurate detection of baicalein,bisphenol molecules and heavy metal ions,respectively.The main research contents and results include:1.A new dumbbell-shaped metal-organic hybrid complex,[Co₄（TC4A）₂]·3DMF·Me OH（Co-TC4A）,was synthesized with the bowl-shaped p-tert-butylthiacalix[4]arene（H₄TC4A）.By a simple one-step solvothermal reaction method,Co-TC4A was embedded and dispersed in ordered mesoporous carbon（OMC）to give composite（Co-TC4A@OMC（1:1））.The synergistic effects between Co-TC4A and OMC drastically enhanced the catalytic efficiency,conductivity and specific surface area of the resulting materials.The glassy carbon electrode modified with Co-TC4A@OMC（1:1）composite（Co-TC4A@OMC（1:1）/GCE）was used in the electrochemical detection of baicalein with a wide linear range of 0.005–17.00μM,a high sensitivity of 8.96μAμM^-1and an ultra-low detection limit of 1.6 n M.In addition,this sensor can also be used for the determination of baicalein in the real drug（baicalein aluminum capsules）with satisfactory recovery.2.Based on H₄TC4A of the previous chapter,the lower edge of the calixarene was modified by four imidazole groups and the bridged sulfur atoms were oxidized to sulphones,resulting in the imidazole groups functionalized sulfonylcalix[4]arene-based ligand（L¹）.Then,a new porous 2D MOF[Zn₂（L）（IPA）（H₂O）]·2DMF·2Me OH·3H₂O（Zn-L-IPA）was synthesized by using L¹,isophthalic acid（H₂IPA）and Zn（Ⅱ）cations.Due to the introduction of hydrochloric acid into the solvothermal reaction,parts of C-O bond of L¹were broken and L¹converted into new ligand（H₂L）.Combined with the host-guest recognition strategy and the electrochemical detection method,a rapid,high-selective and ultrasensitive electrochemical sensing platform（Zn-L-IPA@GP/GCE）was fabricated by using Zn-L-IPA as the host to recognize and adsorb bisphenol guests（GP=graphite powder）.During the accumulation process,1D channels with specific size and structure of Zn-L-IPA showed different adsorption capacities for the three analogous bisphenol substances.Thus,the detection results of bisphenol F（BPF）and bisphenol A（BPA）showed wide linear ranges of0.005–10.50μM and 0.01–8.50μM,respectively,and extremely low detection limits of 0.2and 3.5 n M,respectively.While there was almost no current response to bisphenol S（BPS）.The density functional theory（DFT）calculation results demonstrated that the hydrogen bonding andπ–packing interactions dominated the combining effect between the Zn-L-IPA host and the bisphenol guest.The volume,dipole moment,electronic structure and geometry of guest molecules affect the selective adsorption of guest molecules in the 1D channels.3.Further,under different solvothermal conditions,the dumbbell-shaped tetranuclear bismuth cluster[Bi₄（TC4A）₂（μ₄-O）]·2NO₃·3DMF·3Me OH（Bi₄-TC4A）and the irregular sphere-shapeeight-nuclearbismuthcluster[Bi₈（TC4A）₅（en）₂（μ₃-OH）₂（μ₄-OH）₂]·5DMF·2Me OH（Bi₈-TC4A）were synthesized by the use of H₄TC4A.The constructed electrodes（Bi₄-TC4A/GCE and Bi₈-TC4A/GCE）were applied to detect Cd²⁺and Pb²⁺in aqueous solution by utilizing the unique advantages of Bi-based materials and calixarene ligands in the detection of heavy metal ions.Compared with Bi₄-TC4A/GCE,Bi₈-TC4A/GCE showed the senior detection performances with high sensitivities of 12.71 and 18.14μAμM^-1as well as low detection limits of 12.4 and 8.2 n M for Cd²⁺and Pb²⁺,respectively.Moreover,Bi₈-TC4A/GCE was employed to determine the contents of Cd²⁺and Pb²⁺in real soil and lake water samples.4.By the use of resorcin[4]arene modified by 4-mercaptopyridine（TMC4R）,1,4-benzenedicarboxylic acid（1,4-H₂BDC）and Co（II）cations,a new sulfur-containing nano-capsule-based3DMOF[Co₂（TMC4R）（1,4-BDC）₂（μ₂-H₂O）]·3DMF·CH₃OH·5CH₃CN·H₂O（Co-TMC4R-BDC）was synthesized.And the detection performances of four heavy metal ions(HMIs:Pb²⁺,Cu²⁺,Cd²⁺and Hg²⁺)was systematically evaluated on the Co-TMC4R-BDC modified electrochemical sensing platform（Co-TMC4R-BDC/GCE）.Under the optimized detection conditions,the HMIs sensing platform showed significantly enhanced electrochemical sensing behavior because the Co-TMC4R-BDC featured even-distributed sulfur atoms,special cavity structure and acceptable conductivity.Most strikingly,the limit of detection（LOD）values for Cd²⁺,Pb²⁺and Cu²⁺are up to 26.4,11.2 and 13.3 n M,respectively,which are lower than the standard level of drinking water from the World Health Organization.Moreover,the Co-TMC4R-BDC modified electrode possessed good stability,prominent reproducibility and great potential for the practical application.X-ray photoelectron spectroscopy（XPS）results confirmed that the exposed S atoms of the nano-capsule units effectively captured HMIs through the complexation between S atoms and HMIs.Further,DFT calculations indicated the presence of cation-πinteractions between phenyl rings and HMIs.Thereby,it is reasonable to infer that the synergistic effects accomplished the effective capture for the sensitive detection of HMIs.This work provides a feasible strategy for the capture and electrochemical detection of HMIs in an aqueous solution with the sulfur-containing nano-capsule shaped MOF.更多还原