【作者】 张萌；

【导师】 仰大勇； 阮昕华；

【作者基本信息】 天津大学 ， 生物工程， 2020， 硕士

【摘要】 稀土具有锐线发射、荧光寿命长、量子产率高等优良的光物理性能,将稀土元素引入超分子凝胶网格中所制备的多功能材料,在生物分析、荧光传感等领域有重要的应用价值。利用超分子金属配位键的动态性,使制备的凝胶体系具有可逆的刺激响应性。本论文基于核苷/稀土与DNA/稀土配合物,制备了三种超分子发光凝胶体系,并对其化学结构,光学性能和刺激响应性进行了研究,主要研究工作归纳如下:1.以DNA的重要组分——胸腺嘧啶核苷（T）为配体,与镧系离子(Ln³⁺)配位形成Ln³⁺/T配合物。随后,在Ln³⁺/T配合物中掺入具有蓝光发射的碳点（CDs）,并进一步通过自组装制备了荧光变色超分子水凝胶。通过调节Ln³⁺/T配合物与CDs的化学计量比,得到了高度可调的荧光颜色,其中包括白光发射。水凝胶在离子、p H和温度等外界刺激下具有可逆的荧光变色响应,可用于智能荧光材料的装配。2.在制备的Ln³⁺/T/CDs水凝胶的基础上,进一步冷冻干燥得到了Ln³⁺/T/CDs气凝胶。通过精准调节Ln³⁺/T配合物和CDs之间的化学计量比,得到了一系列荧光颜色可调的气凝胶。当Eu³⁺、Tb³⁺和CDs的化学计量比为1:199:33时,可以实现纯白光发射,量子产率高达47.4%。此外,基于Ln³⁺/T的动态配位键,气凝胶在离子、p H、温度和湿度等刺激下具有可逆的荧光变色响应性。3.以单链DNA（ss DNA）为配体,与Ln³⁺相互作用制备了具有荧光变色性能的水凝胶。通过调节ss DNA碱基的种类和序列的长度可以调控Ln³⁺的发光。研究了水凝胶体系中Tb³⁺与Eu³⁺的共振能量转移,揭示了水凝胶荧光颜色可调的机理。此外,ss DNA与Ln³⁺的之间的动态配位键使水凝胶在Ag⁺和L-半胱氨酸刺激下具有可逆的荧光响应。本论文开发了一系列基于稀土配合物的超分子凝胶系统,研究了其化学结构、光学性能和刺激响应性,在检测、传感和功能材料等领域具有巨大的应用潜能,有助于新一代显示材料、化学/生物传感器及智能发光材料的构筑和研究。更多还原

【Abstract】 Rare earth have excellent photoluminescent properties such as sharp emission,long fluorescence lifetime,and high quantum yield.Multifunctional materials prepared by introducing rare earth into supramolecular gel system have important application value in the fields of biological analysis and fluorescence sensing.Utilizing the dynamic properties of supramolecular metal coordination bonds,the prepared gel system have reversible responsiveness upon external stimuli.In this thesis,three supramolecular luminescent gel systems were prepared based on nucleoside/rare earth complexes and DNA/rare earth complexes,and their chemical structures,photoluminescent properties and stimuli responsiveness were studied.The main research work is summarized as follows:1.Thymidine（T）,an important component of DNA,was used as a ligand to coordinate with lanthanide ions(Ln³⁺)to form the Ln³⁺/T complex.Subsequently,carbon dots（CDs）with blue light emission were doped in the Ln³⁺/T complex,and the fluorochromic supramolecular hydrogels were further prepared by self-assembly process.By adjusting the stoichiometric ratio of the Ln³⁺/T complexes and CDs,the fluorescence color was highly tunable,including white light emission.The hydrogel has a reversible fluorochromic responsiveness under a series of external stimuli such as ions,p H and temperature,and can be used for the construction of smart fluorescent materials.2.Ln³⁺/T/CDs aerogels were obtained by freeze-drying on the basis of the hydrogels prepared in Ln³⁺/T/CDs hydrogels.By precisely adjusting the stoichiometric ratio between Ln³⁺/T complexes and CDs,a series of aerogels with tunable fluorescent colors can be obtained.When the stoichiometric ratio of Eu³⁺,Tb³⁺,and CDs was 1:199:33,pure white light emission（WLE）achieved,and the quantum yield was as high as 47.4%.In addition,based on the dynamic coordination bond between Ln³⁺and T,the aerogel has reversible fluorochromic responsiveness under the stimuli of ions,p H,temperature and humidity.3.Fluorochromic hydrogel was prepared by using single-stranded DNA（ss DNA）as ligand to coordinate with Ln³⁺.The fluorescence intensity of Ln³⁺can be regulated by adjusting the species of bases and sequence length of ss DNA.By studying the resonance energy transfer between Tb³⁺and Eu³⁺in the hydrogel system,the mechanism of the fluorescence color tunability of hydrogel is revealed.In addition,the dynamic coordination bonds between ss DNA and Ln³⁺enable the hydrogel to have a reversible stimuli responsiveness under the stimuli of Ag⁺and cysteine.Three kinds of supramolecular gel systems based on rare earth complex have been developed.The chemical structure,photoluminescent properties and stimuli responsiveness have been studied,and they show great application potential in the fields of detection,sensing and functional materials.They are helpful for the construction and research of new display materials,chemical/biosensors and intelligent light-emitting materials.更多还原