Metal‐free hydroarylation derived ferrocene‐dihydrocoumarin as ultrasensitive dual‐channel probe selectively for picric acid

Abstract

4‐Ferrocenyl‐6,7‐dimethoxy‐3,4‐dihydrocoumarin (3) was synthesized by intermolecular hydroarylation of phenol from β‐ferrocene acrylic acid, and structure has been thoroughly characterized and confirmed by analysing X‐ray single‐crystal data. Compound 3 serves as highly selective fluorescent probe towards explosive picric acid (PA) through quenching of fluorescence in aqueous media. Probe 3 ensures high selectivity for PA in the background presence of various nitroaromatics, anions, cations and some phenols. The LoD for PA has been estimated to be 25.0 ppb using fluorescent probe 3. Binding stoichiometry and binding site of 3 towards PA have been supported by Job's plot, ESI‐mass, performing NMR titration and eventually by developing a model compound 4‐ferrocenyl‐3,4‐dihydrocoumarin 4, which strongly suggested 6,7‐dimethoxy groups as best probable binding site for PA. Overall, present approach deals with development of a ferrocenyl‐dihydrocoumarin conjugate for highly selective and ultrasensitive ‘turn‐off’ fluorescent probe for PA, which has been well‐supported through rational spectral analyses as well as through synthesizing a model compound.

A multi-cation responsive Ni(ii)-supramolecular metallogel mimics a molecular keypad lockviareversible fluorescence switching

“…It is evident from these values that the average lifetime (τ avg ) of MG is increased upon interaction with Zn 2+ , whereas it is decreased with Cu 2+ and Hg 2+ . 45,46 Higher τ avg for MG + Zn 2+ suggests its existence for a longer period in the excited-state relative to that of MG, whereas lower τ avg for MG + Cu 2+ and MG + Hg 2+ indicates their more rapid excited state decay in comparison to that of MG. Overall, the significant changes in the excited state lifetimes of the compounds MG + Zn 2+ , MG + Cu 2+ and MG + Hg 2+ strongly supported the reversible cation detection using MG.…”