Department of Chemistry, Gauhati University, Guwahati, 781014, Assam, India.
J Fluoresc. 2013 Nov;23(6):1173-8. doi: 10.1007/s10895-013-1248-0. Epub 2013 Jun 26.
A new fluorescent probe for Mn(2+) ion, (6E)-N-((E)-1,2-diphenyl-2-(pyridin-2-ylimino)ethylidene)pyridin-2-amine (L), has been synthesized from benzil and 2-amino pyridine and characterized. In 1:1 (v/v) CH3CN:H2O (pH 4.0, universal buffer) L exhibits fluorescent intensity with emission peak at λmax 360 nm on excitation with photons of 310 nm. Fluorescent intensity of L increases distinguishingly on interaction with Mn(2+) ion compared to metal ions--Na(+), K(+), Ca(2+), Mg(2+), Ba(2+), Fe(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+), Pb(2+) and Ag(+) individually or all together. The enhancement in fluorescent intensity is due to snapping of photoinduced electron transfer (PET) prevailed in free L. Fluorescence and UV/visible spectral data analysis shows that binding stoichiometry between Mn(2+) and L is 1:1 with log β ≈ 3.0. Both L and its Mn(2+) complex were optimised using density functional theory (DFT) and vibrational frequency calculations confirm that both are at local minima on the potential energy surfaces.
一种新的用于 Mn(2+)离子的荧光探针，（6E）-N-((E)-1,2-二苯基-2-(吡啶-2-亚基)亚乙基)吡啶-2-胺（L），已经由苯甲酰和 2-氨基吡啶合成并进行了表征。在 1:1（v/v）CH3CN:H2O（pH 4.0，通用缓冲液）中，L 在 310nm 光激发下于 λmax 360nm 处显示出荧光强度，发射峰。与金属离子- Na(+)、K(+)、Ca(2+)、Mg(2+)、Ba(2+)、Fe(2+)、Co(2+)、Ni(2+)、Cu(2+)、Zn(2+)、Cd(2+)、Hg(2+)、Pb(2+)和 Ag(+)相比，L 与 Mn(2+)离子相互作用时荧光强度明显增强。荧光强度的增强归因于自由 L 中存在的光诱导电子转移（PET）的断裂。荧光和紫外/可见光谱数据分析表明，Mn(2+)与 L 之间的结合比为 1:1，log β≈3.0。使用密度泛函理论（DFT）对 L 和其 Mn(2+)配合物进行了优化，振动频率计算证实两者都在势能表面上处于局部最小值。
