Synthesis and Structural Characterization of Azine Based Chemosensors for Ag+ Ion Detection and Their Theoretical Investigations

A novel azine monomer and its oligomeric esters were synthesized and applied to chemosensor applications. Among the series of metal ions, the fluorophores show selective and sensitive “turn off” response towards Ag+ ions. The stoichiometry and binding constant are calculated using the Stern‐Volmer equation and Benesi‐Hildebrand plots, respectively. The fluorophore‘s capability for quantitative analysis of Ag+ ions was studied. The quenching mechanism LMCT and PET behind the “turn off” response was confirmed. The conductivity nature of iodine doped and undoped oligoesters was studied. The dielectric behaviour of oligoesters was also studied to determine the possibility of oligoesters in making passive components such as capacitors and resistors. All the results obtained from chemosensor and electrical studies were validated using a theoretical (DFT) analysis using B3LYP/6–311++G(d,p) level basis set. A novel azine monomer and its oligomeric esters were synthesized and applied to chemosensor applications. The fluorophores show selective and sensitive “turn off” responses towards Ag+ ions. The fluorophore‘s ability to quantitatively analyse Ag+ ions. The structure and monodispersed nature of oligoesters were confirmed by GC‐MS and GPC chromatograms. TGA results demonstrated good extinguishing behaviour, contact angle measurements revealed a hydrophilic nature, and UV‐Vis and fluorescence spectra revealed a larger band gap and fluorescence intensity than monomer. Fluorophores selectively detected Ag+ ion in the chemosensor study and demonstrated ′turn off′ response. The Stern‐Volmer and Benesi‐Hildebrand plots are used to calculate fluorophore binding constants and stoichiometry. These values demonstrate that oligoesters are more efficient than monomers. Interference, time effect, and pH studies show that fluorophore is sensitive to Ag+. Fluorophores reversibility study with Ag+ ions in the presence of EDTA demonstrates fluorophores′ ability to sense Ag+ ions for many cycles. Fluorophores show a good response and recovery level with Ag+ ion in real water analysis. The lack of permeability into the cell wall is responsible for the absence of expected cell image studies of DPHMP and DPHMP‐Ag+ with THP‐1. The quenching mechanism behind the “turn off” response and the conductivity and dielectric behaviour of oligoesters were studied. DFT studies explain quenching, binding sites and LMCT of fluorophores with Ag+ ion.