一种可用于检测环境中微量抗生素残留的荧光d₁₀金属配合物

A Fluorescent d₁₀ Metal Coordination Polymer Capable of Detecting Trace Antibiotic Residues in the Environment

我们使用了一种半刚性的咪唑-4,5-二甲酸衍生物配体(H3L-1)和辅助的刚性苯联双咪唑(BIMB)与d10金属Cd(II)离子在180ºC的水热条件下作用成功得到了一种无色的块状晶体。经单晶X-射线衍射测定和分析后发现该晶体的分子式为[Cd(L)(BIMB)0.5]n(1),它具有两重穿插的三维柱撑–层状骨架结构,其中原始的H3L-1配体在高温下发生了原位脱羧变成L2−阴离子形式。收集后的多晶样品经过粉末X-射线测定表明样品具有较高的相纯度。该化合物还展示出了较好的热稳定性和化学稳定性。配合物的固态荧光光谱表征发现其具有源自于配体自身π电子跃迁所致的强烈的蓝色荧光发射。此外,我们还测定了该配合物粉末样品浸没在多种常见的抗生素分子的DMF悬浊液中的荧光强度变化,分析了其对抗生素分子的荧光传感能力,结果表明该配合物可用于检测以呋喃妥英(NFT)为代表的抗生素分子,研究发现在低浓度范围内配合物荧光强度与抗生素分子浓度呈线性关系,经计算得到检出限(LOD)为1.07 × 10−5 mol∙L−1。

A colorless bulk crystal of good quality was obtained by the hydrothermal reaction of a semirigid imidazole-4, 5-dicarboxylic acid derivative ligand (H3L-1) and an auxiliary rigid BIMB ligand with d10 metal Cd2+ ions at 180˚C. The molecular formula of the crystal was found to be [Cd(L)(BIMB)0.5]n (1) by single X-ray diffraction analysis and it exhibits a 2-fold interpenetrated three-dimensional (3D) pillarlayered framework, in which the original H3L-1 ligand decarboxylases in situ to L2− anion form at high temperature. After the collection of polycrystalline samples, the powder X-ray diffraction analysis showed that the as-synthesized samples have high crystal purity. In addition, complex 1 also showed good thermal and chemical stability. Solid state fluorescence spectra of complex 1 show that it exhibits a strong blue fluorescence resulting from the intraligand πelectron transition. In addition, we also measured the change of fluorescence intensity of complex 1 immersed in DMF suspension of a variety of common antibiotic molecules, and analyzed its fluorescence sensing ability on antibiotic molecules. The results showed that complex 1 could be used to detect antibiotic molecules represented by NFT. It was found that the fluorescence intensity of the complex 1 had a linear relationship with the concentration of antibiotic molecules in the low concentration range, and the limit of detection (LOD) was calculated to be 1.07 × 10−5 mol∙L−1.