一种锌配合物用于炭疽生物标志物的检测

A zinc complex for the detection of anthrax biomarker

采用溶剂热合成方法,合成了一种新型金属配位聚合物{[Zn_(2)(L)(H_(2)O)(DMA)]·DMA·2.3H_(2)O}_(n)(1),其中L4-为完全脱去质子的N,N'⁃二(4⁃羧基苄基)⁃5⁃氨基间苯二甲酸,DMA为N,N⁃二甲基乙酰胺。单晶X射线衍射结果显示,该配合物属于三斜晶系,空间群为P1,a=0.9896(5)nm,b=1.3705(5)nm,c=1.3821(5)nm,α=80.067(5)°,β=76.729(5)°,γ=76.611(5)°,结构是由二维金属有机层通过π…π相互作用而扩展成的三维超分子骨架。红外光谱验证了锌离子与L4-配体成功配位。粉末X射线衍射(PXRD)实验证实了配合物1具有较高的纯度。热重分析结果显示配合物1在室温至416.9℃区间内具有较好的热稳定性。在273 nm的激发光下,配合物1在437 nm处有较强的荧光发射,可以在30 s内快速检测乙醇溶液中的炭疽生物标志物——吡啶⁃2,6⁃二甲酸,具有选择性高、抗干扰能力强、检测限低(约为15μmol·L^(-1))等特点。结合PXRD图和紫外可见吸收光谱揭示了其检测机理为晶体骨架坍塌而诱导的荧光猝灭。

A novel metal coordination polymer{[Zn_(2)(L)(H_(2)O)(DMA)]·DMA·2.3H_(2)O}_(n)(1)has been isolated under solvothermal method,where L4-is the four⁃deprotonated N,N'⁃bis(4⁃carboxybenzyl)⁃5⁃aminoisophthalic acid and DMA is N,N⁃dimethylacetamide.Single crystal X⁃ray diffraction results showed that the complex belongs to the triclinic crystal system with the space group of P1,a=0.9896(5)nm,b=1.3705(5)nm,c=1.3821(5)nm,α=80.067(5)°,β=76.729(5)°,γ=76.611(5)°and the structure of complex 1 is a 3D supramolecular framework that expanded by 2D metal⁃organic layers throughπ…πinteractions.Interestingly,a“bowl”shaped structure exists in the 2D layer,and the center of the“bowl”is a cavity with a size of about 1.493 nm×1.503 nm,which can be used to load a certain volume of guest molecules.Infrared spectroscopy verified the successful coordination of zinc ions with the L4-ligand.Powder X⁃ray diffraction(PXRD)experiments confirmed that complex 1 had high purity.Thermo⁃gravimetric analysis showed that complex 1 had good thermal stability in a range from room temperature to 416.9℃.Under the excitation light of 273 nm,complex 1 exhibited strong fluorescence emission at 437 nm in an ethanol solution,which could quickly detect the anthrax biomarker of pyridine⁃2,6⁃dicarboxylic acid(DPA)through fluores⁃cence quenching within 30 s.The results of concentration⁃dependent experiments showed that there was a good lin⁃ear relationship between the concentration of DPA and the fluorescence intensity of complex 1,with R2=0.99651 and a quenching constant value of 4.052×10^(4)L·mol^(-1).The calculated limit of detection was approximately 15μmol·L^(-1),which was significantly lower than the infection dose of anthrax spores(60μmol·L^(-1)).After adding various inter⁃ferents to the solution of complex 1,the change in fluorescence intensity of complex 1 was negligible.However,when DPA was added,the fluorescence intensity decreased significantly,indicating that complex 1 had a high selec⁃tivity for DPA.The detection mechanism was revealed by combining PXRD patterns and UV⁃Vis absorption spectra,which is fluorescence quenching induced by the collapse of the crystal framework.CCDC:2355003.