Bhardwaj Kanishk, Anand Thangaraj, Jangir Ritambhara, Sahoo Suban K
Department of Chemistry, Sardar Vallabhbhai National Institute Technology, Surat, 395007, Gujarat, India.
Department of Chemistry, Sathyabama Institute of Science and Technology, Chennai, 600119, India.
J Fluoresc. 2024 May;34(3):1065-1074. doi: 10.1007/s10895-023-03347-4. Epub 2023 Jul 15.
An aggregation-induced emission enhancement (AIEE) active Schiff base PNN was synthesized by condensing benzidine with 2-hydroxynaphthaldehyde. The green-fluorescent PNN (λ = 510 nm) in DMF turned to yellow-fluorescent PNN (λ = 557 nm) upon increasing the fractions of HEPES buffer (10 mM, pH 7.4) above 40%. The DLS study supports the self-aggregation of PNN that restricts the intramolecular rotation and activates the excited-state intramolecular proton transfer (ESIPT) process. The fluorescence emission of AIEE active PNN was quenched by Cu with an estimated detection limit of 2.1 µM. Interestingly, the detection limit of PNN towards Cu was improved in the presence of an AIEE inactive Schiff base PBPM obtained by reacting 1,4-diaminobenzene with pyridine-4-carbaldehyde. The mixed PNN-PBPM showed a detection limit of 0.49 µM. The practical utility of PNN-PBPM was validated by quantifying Cu ions in real environmental water samples and green tea.
通过联苯胺与2-羟基萘甲醛缩合合成了一种聚集诱导发光增强（AIEE）活性席夫碱PNN。当HEPES缓冲液（10 mM，pH 7.4）的比例增加到40%以上时，DMF中的绿色荧光PNN（λ = 510 nm）转变为黄色荧光PNN（λ = 557 nm）。动态光散射（DLS）研究支持PNN的自聚集，这种自聚集限制了分子内旋转并激活了激发态分子内质子转移（ESIPT）过程。AIEE活性PNN的荧光发射被铜淬灭，估计检测限为2.1 μM。有趣的是，在由1,4-二氨基苯与吡啶-4-甲醛反应得到的AIEE非活性席夫碱PBPM存在下，PNN对铜的检测限得到了改善。混合的PNN-PBPM的检测限为0.49 μM。通过对实际环境水样和绿茶中的铜离子进行定量，验证了PNN-PBPM的实际应用价值。
