Sensitive discrimination of hazardous explosives by a sensor array based on siloles with aggregate-induced emission

Abstract

The utilization of cationic amidinourea as side chain of fluorophore has rarely been reported, which might be an efficient and feasible strategy for detecting hazardous explosives. In this work, we present an organic sensor bearing a cationic amidinourea group—specifically, silole UMPS-synthesized via a rapid and convenient method. Its analogues with novel and symmetric structures were also reported. One is neutral and the other two carry hydrocarbon side chains that are positively charged. All four derivatives exhibit aggregation-induced emission and were employed for the detection of nitroaromatic explosives in water. These silole-based derivatives demonstrate excellent sensitivity and effective discriminatory capabilities in detecting explosives. We constructed a cross-reactive sensor array consisting of four derivatives, enabling the differentiation of nine closely related nitro explosives through linear discriminant analysis (LDA). This sensor array not only effectively distinguishes individual explosives of different concentrations and complex explosive mixtures, but also has the capability to identify individual explosives in real water samples with the assistance of machine learning algorithms. Moreover, two siloles were fabricated into test strips for sensing nitroaromatics in practical applications. We anticipate that the current work will pave the way for the development of cation sensors and provide a convenient detection platform for environmental analysis.