Aggregation induced emission based fluorenes as dual-channel fluorescent probes for rapid detection of cyanide: applications of smartphones and logic gates

Shumaila Majeed; Muhammad Tahir Waseem; Hafiz Muhammad Junaid; Gul Shahzada Khan; Shamyla Nawazish; Tariq Mahmood; Asad Muhammad Khan; Sohail Anjum Shahzad

doi:10.1039/d2ra03119a

Aggregation induced emission based fluorenes as dual-channel fluorescent probes for rapid detection of cyanide: applications of smartphones and logic gates

RSC Adv. 2022 Jun 29;12(29):18897-18910. doi: 10.1039/d2ra03119a. eCollection 2022 Jun 22.

Authors

Shumaila Majeed¹, Muhammad Tahir Waseem¹, Hafiz Muhammad Junaid¹, Gul Shahzada Khan², Shamyla Nawazish³, Tariq Mahmood^{1

2}, Asad Muhammad Khan¹, Sohail Anjum Shahzad¹

Affiliations

¹ Department of Chemistry, COMSATS University Islamabad, Abbottabad Campus University Road Abbottabad 22060 Pakistan sashahzad@cuiatd.edu.pk.
² Department of Chemistry, College of Science, University of Bahrain Sakhir 32038 Bahrain.
³ Department of Environmental Sciences, COMSATS University Islamabad, Abbottabad Campus Abbottabad 22060 Pakistan.

Abstract

Rational modification of molecular structure by incorporating electron donating groups can play a potential role for designing aggregation induced emission (AIE) active fluorescent probes. Based on this principle, fluorescent probes (1a-c) were synthesized, and they displayed excellent aggregation induced emission (AIE) behavior in a H₂O/DMF (4 : 1, v/v) mixture due to restrictions in intramolecular charge transfer (ICT). As a comparison, probe 1d was synthesized by installing an electron withdrawing (-NO₂) group that surprisingly quenched the aggregation behaviour. Additionally, AIE active probes 1a-c displayed a highly sensitive dual channel (fluorometric and colorimetric) response towards rapid detection of CN^-, which is an active toxic material. Probes 1a-c showed selectively enhanced fluorescence emission behavior towards CN^- with detection limits of 1.34 ppb, 1.38 ppb, and 1.54 ppb, respectively. The sensing mechanism involves Michael type adduct formation due to the nucleophilic addition reaction of cyanide with probes and was confirmed through ¹H NMR titration experiments. In contrast, probe 1d containing an electron withdrawing moiety showed insensitivity towards CN^-. Therefore, this study provides the efficient strategy to induce AIE character in fluorescent probes and expands the mechanistic approach toward the sensing of toxic CN^-.