Abstract
The coumarin-naphthalene conjugate (A3), an ESIPT-active probe, selectively recognized OCl(-) in a ratiometric manner in DMSO-water media. The recognition was associated with sky-blue emission (under UV light) as well as yellow emission (under visible light). The OCl(-) assisted inhibition of the ESIPT process via H-bonding resulted in an intense emission at 484 nm (λ (ex) = 365 nm). It allowed for the detection of OCl(-) as low as 18.42 nM with a strong association constant, K = 1.08 × 10(5) M(-1), around physiological pH. Furthermore, the A3-OCl(-) adduct (Ad1) ratiometrically detected Y(3+) via bright orange emission at 556 nm (λ (ex) = 440 nm) under both UV and visible light. Detection up to 98.51 nM was achieved with a binding constant, K = 1.38 × 10(5) M(-1), at physiological pH. Density functional theory (DFT) and lifetime decay measurements substantiated the interactions. Real sample analysis were also achieved with the developed method.