Synthesis of trifunctional indole-imine-based Ag NPs as a molecular probe for selective colorimetric detection of Cd(ii), photo-catalytic and antimicrobial agent

Abstract

In the present study, a novel N-(4′-methylphenyl) (4,6-dimethoxy-2,3-diphenyl-1H-indol-7-yl)methanimine 6 (indole imine 6) was synthesized in good yield and was characterized through FT-IR, UV-Vis, GC-MS, ¹H/¹³C NMR, and single crystal XRD techniques. The resulting indole-imine Schiff base serves a dual role as both a reducing and stabilizing agent for the single-pot synthesis of AgNPs-6 in a non-aqueous medium. These AgNPs-6 were then characterized using UV-Vis, FT-IR, Scanning-Electron-Microscopy-Energy-Dispersive-X-Rays (SEM-EDX), Dynamic Light Scattering (DLS), and Zeta Potential measurement. The synthesized AgNPs-6 demonstrated remarkable trifunctionality: it operated as a sensitive colorimetric nano probe for Cd²⁺ detection (LOD = 27.8 nM), exhibited strong photocatalytic activity with 95% methylene blue degradation under sunlight, and showed enhanced antibacterial performance through synergistic interaction between the silver core and organic ligand. This work establishes a rational design strategy for multifunctional nanomaterials that integrate detection, degradation, and disinfection capabilities within a single platform.