The cooperative action of multiple non-covalent interactions allowed for the assembly of a new series of Pb ^II coordination compounds.

An efficient Al³⁺ receptor, 6-(2-hydroxybenzylideneamino)-2H-chromen-2-one (HBC), has been synthesized by condensing salicylaldehyde with 6-aminocoumarin. The molecular structure of HBC has been determined by a single crystal X-ray analysis. It was established that in the presence of Al³⁺, HBC shows 25 fold enhancement of fluorescence intensity which might be attributed to the chelation-enhanced fluorescence (CHEF) process. HBC binds Al(NO₃)₃ in a 1 : 1 stoichiometry with a binding constant (K) of 7.9 × 10⁴ M⁻¹. Fe³⁺ and Mn²⁺ quench the emission intensity of the [HBC + Al³⁺] system to an insignificant extent at a concentration 10 times higher compared to that of Al³⁺. HBC is highly efficient in the detection of intracellular Al³⁺ under a fluorescence microscope.