Fabrication of a novel AIE active chemosensor for selective detection of Pd(ii) and picric acid: extended detection in the HeLa cancer cell line

Abstract

The development, identification, and chemosensing activity of a Schiff base chemosensor, (E)-2-(2-((5-bromo-2-hydroxybenzylidene)amino)propyl)-3′,6′-bis(diethylamino)spiro[isoindoline-1,9′-xanthen]-3-one (RBSB), is reported in this study. Simply condensing 5-bromo salicylaldehyde and rhodamine-1,2 diamino propane derivative (RBN) yields the Schiff base RBSB. Numerous spectroscopic, scanning electron microscopy (SEM), and dynamic light scattering (DLS) investigations validate the probe's AIE active characteristic in a 1 : 9 DMSO–water medium, where the probe shows luminescence properties. It is noteworthy that the developed probe exhibits a turn-on fluorescence response in an aggregation-induced emission (AIE) active medium, enabling the selective detection of Pd(II) ions and picric acid. Upon binding with the target analyte, the spirolactam ring of the rhodamine moiety in RBSB undergoes a ring-opening process, triggering a significant enhancement of fluorescence emission. The 1 : 1 stoichiometric combination of the probe and target analytes is confirmed using mass and NMR spectrum analysis. The probe–analyte adduct structure is optimized by implementing density functional theory (DFT) analysis. The fluorescent microscopic images of the HeLa cancer cell line confirm the biosensing activity of the target probe.