含吡啶环香豆素酸性pH荧光探针的合成及应用

Synthesis and application of acid pH fluorescent probes containing pyridine ring coumarin

为实现强酸性环境下pH的准确测量,设计并合成3个酸性p H荧光探针。经Knovengel反应得到3-乙酰基-7-二乙胺基香豆素(化合物1),再四组分一锅法得到2-氨基-3-氰基-6-(7-二乙胺基)香豆素吡啶衍生物(探针L-1、L-2、L-3),通过~1H NMR,^(13)C NMR,LC-MS对探针的结构进行表征,并用荧光光谱法对其光谱性能进行研究。探针L-1、L-2和L-3对H^+都有良好的选择性,其pKa分别为2. 68,2. 07和1. 99。探针L-1、L-2和L-3线性响应范围分别为pH 1. 59～3. 40,pH 1. 25～3. 43和pH 1. 14～3. 23,相关系数分别为0. 9930,0. 9919和0. 9907,3个探针均不受其他阳离子的干扰且具有可逆性。

In order to achieve accurate measurement of pH in strong acidic environment,three pH fluorescent probes were designed and synthesized.First,3-acetyl -7-diethylaminocoumarin (Compound 1 )was obtained by Knovengel reaction.Then,2-amino -6 -(7-(diethylamino)-2- oxo -2H-chromen -3-yl)nicotinonitrile derivatives (L -1,L -2 and L -3 )were synthesized by one-pot four-components condensation reaction.The structures of these probes were characterized by 1H NMR,13C NMR and LC-MS and their spectral properties were studied by fluorescence spectroscopy.L-1,L -2 and L -3 probes displayed excellent pH dependent performance with pKa of 2.68,2.07, 1.99,respectively.The pH titrations indicated that probe L-1 responded linearly (R^2 =0.9930)to pH within the extremely acidic range of 1.59~3.40.Meanwhile,there was also a good linearity (R^2 =0.9919)for L-2 between fluorescence intensity and pH in the range of 1.25~3.43.Similar results were obtained for probe L -3.Three probes displayed excellent stability and reversibility to hydrogen ion.