A new turn-on fluorescent chemosensor based on sensitive Schiff base for Mn2+ ion
A new turn-on fluorescent chemosensor based on sensitive Schiff base for Mn2+ ion
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DOI：
10.1016/j.jlumin.2015.04.040
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发表时间：
2015-09
影响因子：
3.6
通讯作者：
N. Roy;Abhijit Dutta;P. Mondal;P. Paul;T. S. Singh
中科院分区：
文献类型：
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作者：
N. Roy;Abhijit Dutta;P. Mondal;P. Paul;T. S. Singh
合成了一种席夫碱荧光探针- N，N′-双（（6-（噻吩-3-基）吡啶-2-基）亚甲基）苯-1，2-二胺（L）。在乙醇溶液中，Mn ~（2+）与L ~（2+）的络合作用使L ~（2+）的荧光发射强度明显增强，并产生红移。此外，其他常见的碱金属、碱土金属和过渡金属离子未能引起响应或最小的光谱变化。对L-Mn ~（2+）配合物的荧光光谱研究表明，配位后量子产率显著增加。L与Mn ~（2+）形成的络合物溶液与EDTA反应可逆，可再生游离配体用于Mn ~（2+）的检测。使用Benesi-Hildebrand关系评估化学计量比和缔合常数，得到1：1化学计量比。这进一步证实了基于约伯的情节分析的1：1复合体形成。该化学传感器在较宽的酸性pH范围内对Mn 2+表现出非常好的荧光传感能力。该传感器可用于真实的水样中Mn 2+的检测。用密度泛函理论对BothLand和L-Mn ~（2+）配合物进行了优化，并通过振动频率计算证实了两者都处于势能面上的局部极小值。L-Mn ~（2+）配合物的HOMO和LUMO的能量差分别为2.210 eV和0.550 eV，表明L-Mn ~（2+）配合物具有较低的动力学稳定性和较高的化学反应活性。
A Schiff-base fluorescent probe – N,N′-bis((6-(thiophen-3-yl)pyridine-2-yl) methylene) benzene-1,2-diamine (L) – was synthesized and evaluated as a chemoselective Mn2+sensor. Upon treatment with Mn2+, the complexation ofLwith Mn2+resulted in a red-shift with a pronounced enhancement in the fluorescence emission intensity in ethanol solution. Moreover, other common alkali, alkaline earth and transition metal ions failed to induce response or minimal spectral changes. Fluorescence studies onLand L–Mn2+complex reveal that the quantum yield strongly increases upon coordination. The complex solution ofLwith Mn2+ion exhibited reversibility with EDTA and regenerated free ligand for further Mn2+sensing. The stoichiometric ratio and association constant were evaluated using Benesi–Hildebrand relation giving 1:1 stoichiometry. This further corroborated 1:1 complex formation based on Job’s plot analyses. This chemosensor exhibits a very good fluorescence sensing ability to Mn2+over a wide acidic pH range. This chemosensor can be used as an important application for detection of Mn2+in real water samples. BothLand L–Mn2+complex were optimized using density functional theory and vibrational frequency calculations confirmed that both are at local minima on the potential energy surfaces. The corresponding energy differences between HOMO and LUMO ofLand L–Mn2+complex are 2.210 eV and 0.550 eV, respectively which implies a low kinetic stability and high chemical reactivity.