可逆型荧光探针的合成及对Cu2+和Pd2+的双重检测

Synthesis of reversible fluorescent probes and dual detection of Cu2+ and Pd2+

摘要:

利用嘌呤生物骨架为基础，通过简单的席夫碱反应成功合成了一种用于检测溶液中Cu2+和Pd2+的可逆型荧光探针PHM（(E)-4-((2-(8,9-二(萘-1-基)-9H-嘌呤-6-基)肼基)甲基)-2-甲氧基苯酚）。PHM可以快速识别HEPES缓冲溶液系统中的钯离子和铜离子，并且不受其他金属离子的干扰。其在DMSO/H2O溶液(9/1,v/v, pH 7.4, HEPES缓冲液，0.2mmol/L)中对Cu2+和Pd2+的检出限分别为72.97 nmol/L和839 nmol/L。同时，肉眼可以察觉到视觉色调的明显变化，这可能是由于PHM与Cu2+和Pd2+离子的络合，是在抑制光诱导的电子转移效应中产生的，在添加EDTA后PHM-Cu2+的荧光得以恢复，证实了PHM的可逆性。密度泛函理论（DFT）和Job's plot实验均支持了荧光探针与Pd2+和Cu2+离子可能的络合机制。

Abstract:

A novel fluorescent probe on the basis of Schiff base ((E)-4-((2-(8,9-di(naphthalen-1-yl)-9H- purin-6-yl) hydrazineylidene) methyl)-2-methoxyphenol named as PHM) for detecting Cu2+ and Pd2+ ions were designed and structurally described using biological purine scaffolds. This fluorescent probe can quickly recognize palladium and copper ions in the HEPES buffer solution system without interference from the rest of the metal ions. It’s detection limits in HEPES buffer solution for Cu2+ and Pd2+ ions were 72.97 nmol/L and 839 nmol/L, respectively. Meanwhile, naked eyes can detect a visual hue change, which could be due to its complexation with Cu2+ and Pd2+ ions, generated in the inhibition of photo-induced electron transfer effects. The fluorescence of PHM-Cu2+ was restored after the addition of EDTA, confirming the reversible property of PHM. A density flooding theory (DFT) and Job’s plot analysis backed up the binding processes of the fluorescence probe towards Pd2+ and Cu2+ ions.