An Al3 + ion selective chromone-benzohydrazide anchored optical material

In this study, we report a highly sensitive chromone-benzohydrazide-anchored optical material ( CM1 ) for the selective recognition of Al 3+ ions. The crystal structure of CM1 reveals that the molecule adopts a trans orientation, with the chromone and carbonyl oxygen positioned opposite to each other. CM1 exhibits a ‘turn-on’ fluorescence response upon interaction with Al³ ⁺, resulting in enhanced blue fluorescence. The practical applicability of CM1 was further evaluated using test paper strips. The CM1 complexed with Al³ ⁺ in a 1:1 stoichiometry, exhibiting a binding constant of 1.58 × 10⁵ M −1 . It demonstrated the ability to detect Al³ ⁺ ions at concentrations as low as 1.90 × 10⁻⁹ M. The effective binding between CM1 and Al 3+ , along with the underlying sensing mechanism, was investigated through various spectroscopic techniques and further corroborated by theoretical calculations using density functional theory (DFT). • A fluorescent probe ( CM1 ) containing chromone moiety was synthesized. • The crystal structure of CM1 determined. • CM1 selectively detects aluminum ion in ethanol. • A paper strip sensor was successfully developed for on-the-spot aluminum ion detection using CM1 .