Manipulation from multi-physical quantity aspect to steer molecular photophysical property is of great significance in improving sensing performance. Here, this work pioneeringly conducted a fundamental investigation regarding the essence of how physical quantities act on fluorescence behaviors through constructing a thiol-mediating imidazo isoindole fluorophore as the modal molecule, which was further employed to ultra-sensitively detect trace EDA.

By thoroughly analyzing the individual influence as well as the interplay between multi-descriptor, finely modulated electron-donating capability of thiol was proven as the prominent descriptor corelating to the fluorescence intensity. As a result, the model molecule consisted of a thiol with dual-carboxyl exhibits the strongest fluorescence ascribed to the electron-donating ability prompted larger orbital overlapping and oscillator strength.

The elevated fluorescence positively corelated to the increased EDA, endowing an ultrasensitive response to nanomolar-liquid/ppm-vapor, accompanying a dual-mode response composed of a color change and a turn-on green fluorescence. The excellent sensing performances including outstanding selectivity and anti-interference capability facilitated a desirable analysis of EDA in industrial wastewater. Expanding on this preliminary trial, the proposed sensing reagent loaded hydrogel substrate was assembled in a portable detector which gathered the merits of rapid response, automation as well as on-site detection, it was further proven to be practicable and reliable in real environmental application.

We conjecture the insight regarding electron-donating capability predominated fluorescence model would become a representative example in guiding customizable optical molecule from wider perspectives, thereby accelerating practical application in relevant fields of sensing, imaging, catalysis as well as solar cell, etc.

This research progress was published in Angewandte Chemie International Edition entitled as “Electronic Tuning in Reaction-based Fluorescent Sensing for Instantaneous and Ultrasensitive Visualization of Ethylenediamine”.

The work was financially supported by the of National Nature Science Foundation of China, National Natural Science Foundation of China, the Youth Innovation Promotion Association, West Light Foundation of the Chinese Academy of Sciences, Key Research Program of Frontier Sciences.

Schematic diagram of electron-tuning enabled ultrasensitive and visualized detection towards ethylenediamine

Contact:

Prof. DOU Xincun, Prof. ZU Baiyi

E-mail: xcdou@ms.xjb.ac.cn; byzu@ms.xjb.ac.cn

Xinjiang Technical Institute of Physics & Chemistry, CAS