A new perspective on the AIE and ACQ of phosphinine-anchored luminescent materials as visual and ratiometric sensors for Ag+ and Hg2+ ion detection in live cells†

Abstract

The effective synthesis of phosphinine-based (E)-2-((2,6-dicyano-1,1-diphenyl-λ⁵-phosphinin-4-yl)methylene) hydrazine-1-carbothioamide (MHC) and (E)-4-((2-(benzo[d]thiazol-2-yl)hydrazineylidene)methyl)-1,1-diphenyl-λ⁵-phosphinine-2,6-dicarbonitrile (BHP) sensor materials resulted in the characterization of their notable photophysical characteristics, including aggregation, solvatochromism, and sensing ability. Upon application, the ratiometric emission properties of the MHC and BHP probes were evaluated, and they exhibited noteworthy selectivity and sensitivity for silver (Ag⁺) and mercury (Hg²⁺) ions over other metal ions. After conducting a thorough photophysical investigation, the detection limits (LODs) for Ag⁺ and Hg²⁺ were determined to be as low as 8.7 and 8.6 nM for MHC and 280 and 340 pM for BHP, respectively. In addition, MHC and BHP were examined as capable sensing materials for Ag⁺ and Hg²⁺ ions on paper strip-based sensors and bio-images. ¹H NMR titration, HRMS analysis and DFT studies validated the binding processes of MHC and BHP with Ag⁺ and Hg²⁺ ions. These findings contribute to the future development of practical onsite detection of Ag⁺ and Hg²⁺ ions in ecological systems.