Publication in J. Photoch. Photobio. A

JPPC 2024

A pyridyl-benzimidazole based ruthenium(II) complex as optical sensor: Targeted cyanide detection and live cell imaging applications.

S. Naithani, F. Thetiot, V. Yadav, S. Saini, P. Roy, S. Layek, T. Goswami, S. Kumar

Journal of Photochemistry and Photobiology A: Chemistry 2024, 453, 115610, DOI: 10.1016/j.jphotochem.2024.115610

An extreme toxicity of cyanide (CN) ion in diverse environmental media has encouraged significant attention for scheming well-organised molecular probes for its selective and sensitive detection. Keeping in mind, we present here a monometallic Ru(II) complex (Ru-1) based on 2-(pyridin-2-yl)-1H-benzo[d]imidazole moiety acting as a highly selective luminescent probe for CN recognition in pure water. Besides, Ru-1 also acted as an efficient sensor for F, AcO and H2PO4 ions along with CN when acetonitrile was chosen as solvent system. The binding constant (Kb) and detection limit (LoD) for CN have been depicted as 3.05 × 106 M−1 and 12.8 nM, respectively, in water. The close proximity of N-H site with Ru(II) centre along with its remarkable acidity were identified as mainly responsible for the high selectivity of Ru-1 toward CN in water. Job’s plot and DFT analyses were carried out to support the anion binding mechanism. Furthermore, the time-resolved fluorescence (TRF) spectroscopy was performed to assess the cyanide-induced emission lifetime change of Ru-1 in aqueous medium. In order to investigate applied potential, the probe Ru-1 was notably developed into paper-based strips that could readily detect CN ion in mM range via naked eye under 365 nm light illumination, and also adequately employed to detect CN in human breast cancer MCF-7 cell lines and natural food sources (such as apple seeds and sprouting potatoes).