Exploring a new multi-responsive pyranone chemosensor capable of sensing copper ions specifically and selectively through colorimetric, UV-Vis absorption and fluorescence methods is of great importance. In this piece of work, a novel pyranone based Schiff base ligand 4-Hydroxy-6-methyl-3-[1-(2-morpholin-4-yl-ethylimino)-ethyl]-pyran-2-one (DM) was synthesized by the condensation of dehydroacetic acid and 4-(2-aminoethyl) morpholine. The structural determination of ligand DM was executed using distinct spectral techniques i.e., ¹H-NMR, ¹³C-NMR, FT-IR and HR-MS techniques. The reported Schiff base DM showed an immediate colorimetric change from pale yellow to colorless accompanied by a strong change in the UV-Vis absorption band onto the addition of Cu (II) ions. This metal ligand chelation leads a decrease in ICT process. Also the decrease in fluorescence emission intensity of Schiff base DM with Cu (II) ions addition showed its turn-off behavior towards copper ions. Further absorption/ emission titration studies, Job’s plot, HR-MS and ¹H-NMR titration data designated 2:1 stoichiometric ratio between DM and Cu (II) ions respectively. Density functional theory studies were also performed to authenticate the binding mechanism theoretically. The sensitivity of Schiff base DM towards Cu (II) ions was applicable at every pH conditions and at the same time DM exhibited selectivity towards Cu (II) ions with a negligible interference of other metal ions. DM showed a detection limit of 7.7 nM towards copper ions via fluorescence emission studies. The best part about DM is that it has good stability but showed an instant chemical reversibility when titrated with EDTA solution.

探索一种新型的多响应吡喃酮化学传感器，该传感器能够通过比色法，UV-Vis吸收法和荧光法特异性地和选择性地检测铜离子，这一点非常重要。在这项工作中，新型的基于吡喃酮的席夫碱配体4-羟基-6-甲基-3- [1-（2-吗啉-4-基-乙基亚氨基）-乙基]-吡喃-2-酮（DM）是通过脱氢乙酸和4-（2-氨基乙基）吗啉的缩合反应合成。配体DM的结构测定采用独特的光谱技术进行，即 ¹ H-NMR，¹³C-NMR，FT-IR和HR-MS技术。报道的Schiff碱DM显示立即的比色变化，从浅黄色变为无色，并伴随着添加Cu（II）离子后UV-Vis吸收带发生了强烈变化。这种金属配体螯合导致ICT工艺的减少。加入铜（II）离子的席夫碱DM荧光发射强度的降低也表明其对铜离子的关闭行为。进一步的吸收/发射滴定研究，乔布斯图，HR-MS和¹H-NMR滴定数据分别表示DM和Cu（II）离子之间的化学计量比为2：1。还进行了密度泛函理论研究，以从理论上验证结合机理。Schiff碱DM对Cu（II）离子的敏感性适用于每个pH条件，同时DM对Cu（II）离子表现出选择性，而对其他金属离子的干扰可忽略不计。DM通过荧光发射研究显示对铜离子的检测极限为7.7 nM。DM最好的部分是它具有良好的稳定性，但用EDTA溶液滴定时具有即时的化学可逆性。