Assembly of a Zn(ii) coordination polymer of tetrapyridyl tetraene ligands for selective sensing of CrO42−and Fe3+in watervialuminescence quenching and enhancement
Zhan-Yong Yang, Chen Cao, Xiao Sang, Yu-Xuan Hong, Hong Yu, Chun-Yan Ni, Jian-Ping Lang

Four Zn(II)-based coordination polymers (CPs), [Zn(4-tkpvb)(FB)2] (CP1), [Zn(4-tkpvb)(CB)2] (CP2), [Zn(4-tkpvb)(BB)2] (CP3) and [Zn(4-tkpvb)(NTP)]n(CP4), were prepared from solvothermal reactions of Zn(NO3)2·6H2O with 1,2,4,5-tetrakis((E)-2-(pyridin-4-yl)vinyl)benzene (4-tkpvb) in the presence of 3-fluorobenzoic acid (HFB), 3-chlorobenzoic acid (HCB), 3-bromobenzoic acid (HBB) and nitroterephthalic acid (H2NTP). These four compounds were structurally characterized by IR, elemental analysis, powder X-ray diffraction and single-crystal X-ray diffraction.CP1–CP3have similar one-dimensional (1D) zigzag chain structures assembled by 4-tkpvb connecting the [ZnL2] (L = FB, CB, BB) units.CP4displays an unusual 6-fold interpenetrating three-dimensional (3D) net with a ‘dia’ topology formed by linking the 2D [Zn(NTP)(4-tkpvb)]nlayersvia4-tkpvb ligands.CP1–CP4all exhibited luminescence emission in the solid state. The representativeCP3exhibited good water stability in the pH range from 3 to 13. It was revealed to be an intriguing luminescent probe for CrO42−anions in H2O by a selective fluorescence quenching method or Fe3+ions in H2O by selective fluorescence enhancement. The detection limit was 0.679 ppm for CrO42−or 0.429 ppm for Fe3+. The emission quenching process may be ascribed to the overlap between the absorption band of the CrO42−anion and those of the excitation and/or emission bands ofCP3, while the emission enhancement mechanism was likely due to the weak interaction between Fe3+and the uncoordinated pyridyl group inCP3.

组装四吡啶基四烯配体的 Zn(II) 配位聚合物，通过发光猝灭和增强选择性检测水中的 CrO42- 和 Fe3+

四种 Zn(II) 基配位聚合物 (CP)、[Zn(4-tkpvb)(FB)2] (CP1)、[Zn(4-tkpvb)(CB)2] (CP2)、[Zn(4- tkpvb)(BB)2] (CP3) 和 [Zn(4-tkpvb)(NTP)]n(CP4) 由 Zn(NO3)2·6H2O 与 1,2,4 的溶剂热反应制备，在 3-氟苯甲酸(HFB)、3-氯苯甲酸 (HCB)、3-溴苯甲酸 ( HBB) 和硝基对苯二甲酸 (H2NTP）。通过红外光谱、元素分析、粉末X射线衍射和单晶X射线衍射对这四种化合物进行了结构表征。CP1–CP3具有相似的一维 (1D) 锯齿形链结构，由连接 [ZnL2] (L = FB, CB, BB) 单元的 4-tkpvb 组装而成。CP4展示了一个不寻常的 6 重互穿三维 (3D) 网络，其具有通过4-tkpvb 配体连接 2D [Zn(NTP)(4-tkpvb)]n层形成的“直径”拓扑。CP1–CP4在固态都表现出发光。代表CP3在 3 到 13 的 pH 值范围内表现出良好的水稳定性。通过选择性荧光猝灭法发现它是H2 O 中的 CrO42-阴离子或通过选择性荧光发现 H2O中的Fe3+离子的一种有趣的发光探针增强。CrO 42-的检测限为 0.679 ppm或 Fe3+的检测限为 0.429 ppm 。发射猝灭过程可能归因于CrO42-阴离子的吸收带与CP3的激发和/或发射带之间的重叠，而发射增强机制可能是由于Fe3+之间的弱相互作用和CP3中未配位的吡啶基。

DOI:10.1039/d1ce01706c