An Imidazo[1,2‐a]pyridine Derivative That Enables Selective and Sequential Sensing of Cu²⁺ and CN⁻ Ions in Aqueous and Biological Samples

Abstract

We report a triazole appended imidazopyridine based chemosensor (probe 1) for sequential detection of Cu2+ and CN− ions using fluorometry. Probe 1 is fluorescent in aqueous acetonitrile (H2O‐CH3CN, 1:1, v/v) when common metal ions are present, but the fluorescence is quenched when Cu2+ is present. The binding mechanism, quantitative determination and the mode of interaction of Cu2+ with probe 1 are explained using fluorescence spectroscopy, electrospray ionization mass spectrometry and Density Functional Theory (DFT) calculations. The observed detection limit for Cu2+ is found to be (18.17×10−6 M) and it is comparable with those reported for other Cu2+ chemosensors. Further, the 1–Cu2+ complex formation is found to be reversible, and this property has been successfully exploited for the quantitative determination of CN− ions in aqueous acetonitrile. Addition of CN– leads to a complete recovery of fluorescence from 1–Cu2+ complex, permitting the real time detection with the lower limit of detection of CN− being 33.57×10−6 M. The observed experimental results are supported by DFT calculations. A possible application of 1–Cu2+ in fluorescence imaging of Rhizoctonia solani mycelia cells, contaminated with CN− ions, is also represented.

Rotational Isomerization about C−C Single Bond in a Novel ICT Probe Facilitates Naked‐Eye, Colorimetric and Ratiometric Detection of Cobalt in Aqueous Samples**

“…We recently observed that presence of two donor atoms in a chemosensor is sufficient to impart selective binding with specific metal ions [39,40] . In our on‐going effort to develop chemosensors for naked‐eye detection, [38,41,42] we envisaged that compound A would be a suitable candidate for probing specific metal ions as the intramolecular H‐bonding vis‐à‐vis the tautomerisomerization (Scheme 1) would influence metal ion selective binding.…”