Solvent dependent colorimetric, ratiometric dual sensor for copper and fluoride ions: Real sample analysis, cytotoxicity and computational studies

•We developed a new terephthalic acid based diamide probe (BPTH).•It can selectively, colorimetrically and ratiometrically sense the Cu2+ and F− ions.•The probe can sense Cu2+ and F− ions in aqu.DMSO (9:1) and DMSO respectively.•BPTH can sense F− ions as solid and even in environmental water also.•The DFT analysis also done for BPTH, BPTH-2H and BPTH+Cu2+ complex.

A novel colorimetric chemosensor based on terephthalic acid and pyridine aldehyde moiety was designed to detect Cu2+/F− ions in aqueous and DMSO solutions at physiological pH conditions with the detection limit of 0.25 μM and 3 μM for Cu2+/F− ions respectively. The probe was found to be highly selective to sense F− ion rather than CH3COO− and H2PO4− ions. Interestingly, the probe behaved as a promising receptor by detecting F− ions even in ordinary tap water through distinct colour change. Moreover, the chemosensor showed lower cytotoxicity against AGS cancer cells and thus found to be biologically friendly. The reversibility of probe-F− binding was investigated using HCl in UV–vis experiment. The binding mechanism of chemosensor to Cu2+/F− ions was elucidated based on the UV–vis spectroscopy, NMR, ESI-Mass spectroscopy and cyclic voltammogram techniques. Furthermore, theoretical investigation was carried out using Gaussian 09 program.

Graphical abstractThe synthesized probe were effectively used as colorimetric dual chemosensor for F−/Cu2+ ions. The sensing mechanism was properly explained using various spectroscopic methods. The sensitivity of the F− ions were investigated in solid state and environmental water samples.Figure optionsDownload full-size imageDownload as PowerPoint slide