A new intramolecular proton transfer (ESIPT)‐based fluorescent probe for selective visualization of cyanide ion

Abstract

Fluorescent probes for detection of CN − still have many limitations, such as small Stokes shift, irreversible, and background interference, which hamper their applications for on-site detection and bioimaging of CN − . In this work, we design a new CN − -activatable fluorescent probe (named AHMM) containing an ESIPT (excited-state intramolecular proton transfer) and hydrogen bond features, which show a large Stokes shift (225 nm) and molecular structural reversible detection. The probe AHMM exhibits an excellent selectivity for CN − without any interference from other anions in aqueous DMSO system. Furthermore, the mechanism of the interaction of AHMM with CN − is concluded by various experiments. The limit of detection of AHMM for CN − is calculated as low as 4.47 × 10 −8 M, lower than the concentration of CN − deemed acceptable by WHO (World Health Organization). AHMM can recognize CN − in tap water quantitatively and on-site by a smartphone APP. Moreover, food samples such as almond and cassava including CN − are visualized by fluorescence imaging. In addition, the probe shows practical applications of CN − imaging in cells and mice. This concept can be applied for designing multifunctional fluorescent probes with ESIPT and reversible characteristics for detection of CN − .

ESIPT-based probes for cations, anions and neutral species: recent progress, multidisciplinary applications and future perspectives

“…Qiao et al 54 With excellent selectivity, Liu et al 55 developed an iminebased colorimetric and uorogenic probe 27 for detecting CN − (Fig. 22).…”

“…Qiao et al 54 synthesized CN − probe 26 having H-bonding for the ESIPT process with good selectivity in DMSO/H 2 O (8/2, v/v). Probe 26 showed a Stokes shift of 225 nm with excellent sensitivity and LOD of 4.47 × 10 −8 M. Furthermore, 26 was utilised to explore potential applications for CN − detection in tap water, smartphone app based on-field quantification of CN − , fluorescence imaging in almonds and cassava (Fig.…”

Photochemical Mechanisms of Hydroxyquinoline Benzimidazole: Insights from Electronic Structure Calculations and Nonadiabatic Dynamics Simulations

“…The Enol* configuration then undergoes an ESIPT process to yield a keto excited-state configuration (Keto*) that could emit long-wavelength fluorescence. − Many chemical reactions in living organisms contain ESIPT processes. Meanwhile, molecules with ESIPT properties are often applied as high-performance fluorescent probes due to the properties of dual fluorescence emission, large Stokes shifts, and ultrafast excited-state deactivation behavior. − These special properties also make ESIPT materials highly sensitive to solvent polarity. − …”