Basu Srestha, Hajra Archismita, Gayen Chirantan, Paul Anumita
Department of chemistry, Indian Institute of Technology Guwahati, Assam, 781039, India.
Centre for nanotechnology, Indian Institute of Technology Guwahati, Assam, 781039, India.
Chemphyschem. 2020 Apr 20;21(8):809-813. doi: 10.1002/cphc.201901044. Epub 2020 Mar 18.
Herein, we report discrimination of dicarboxylic acids - fumaric acid (FA) and maleic acid (MA) - exhibiting geometrical isomerism, using nanoclusters based luminescent probe having excitation under broad day light. The luminescent probe was designed via complexation reaction between zinc ions and ligands (mercaptopropioinc acid; MPA) stabilizing the gold nanoclusters. This resulted in formation of nanoaggregates exhibiting bright green luminescence upon excitation at 450 nm capable of discriminating between FA and MA upto nanomolar level. The basis of discrimination has been attributed to deprotonation of FA and MA following interaction with MPA moieties present on the surface of the nanoaggregates and being governed by the stability of the respective conjugate base of the geometrical isomers of the dicarboxylic acids. As a consequence of different extent of deprotonation of FA and MA upon interaction with the cluster aggregates, different effect on the luminescence of the aggregates was observed, thus enabling discernible fluorimetric discrimination between FA and MA under visible light excitation.
在此，我们报告了使用基于纳米团簇的发光探针，在强光照射下激发，对呈现几何异构现象的二元羧酸——富马酸（FA）和顺丁烯二酸（MA）进行鉴别。该发光探针通过锌离子与稳定金纳米团簇的配体（巯基丙酸；MPA）之间的络合反应设计而成。这导致形成了纳米聚集体，在450 nm激发时呈现亮绿色发光，能够在纳摩尔水平上区分FA和MA。鉴别依据归因于FA和MA与纳米聚集体表面存在的MPA部分相互作用后的去质子化，并且受二元羧酸几何异构体各自共轭碱的稳定性支配。由于FA和MA与团簇聚集体相互作用时去质子化程度不同，观察到对聚集体发光的不同影响，从而能够在可见光激发下对FA和MA进行可辨别的荧光鉴别。
