Fuente: "milk OR dairy products" RSC Adv. 2026 Mar 26;16(19):16759-16766. doi: 10.1039/d6ra01192f. eCollection 2026 Mar 26.ABSTRACTThe "light-switch" Ru(ii) polypyridine complexes have been developed as a novel fluorescent sensor for rapid and sensitive detection of ReO4 - anions in pure aqueous media. When counterions (Cl-) in aqueous solution are specifically exchanged by ReO4 - anions, the "light-switch" Ru(ii) polypyridine complexes exhibit a significant fluorescence emission enhancement, accompanied by the formation of nanoaggregates. This aggregation is driven by weak interactions with electrostatic attraction, anion⋯π, C-H⋯anion hydrogen bonding and π-π stacking interactions between ReO4 - anions and "light-switch" Ru(ii) polypyridine complexes, which is confirmed by single crystal structure analysis, density functional theory (DFT) and Energy decomposition analysis (EDA). The anion exchange-induced aggregation effect of the Ru(ii) polypyridine complexes demonstrate a potent "light-switch" strategy, capable of rapid response to ReO4 - within 1 s and a limit of quantification of 1.5 nM, below the WHO guideline value for its radioactive analogue 99TcO4 - (1.6 nM), demonstrating potential for monitoring pertechnetate contamination. This work opens a new way for future research based on "light-switch" Ru(ii) polypyridine complexes as turn-on fluorescent sensing probes for ReO4 -/99TcO4 - anions detection in aqueous media.PMID:41909800 | PMC:PMC13019534 | DOI:10.1039/d6ra01192f