A Dual Emissive Metal–Organic Framework for Detection of Aluminum Salts in the Solid State with the Naked Eye

Abstract A desolvated form of solid‐state dual emissive fluorophore MOF {[Zn(dim)(dht)](H 2 O) 2 (MeOH)} n ( 1 ) has been selected ( 1′ ); to detect and separate some common aluminum salts, like Al(NO 3 ) 3 , AlCl 3 , and Al 2 (SO 4 ) 3 through naked eye color switching, fluorescence emission spectra and time resolve fluorescence spectra. Here, these aluminum salts change their color in solid state, among the groups of colorless/white metal salts after mechanically grinding with 1′ in solid state. The dual emissive compound 1′ switch to single emissive due to the interaction with aluminum salts exclusively among other colorless/white metal salts. This fluorescence emission changes are fully supported by the fluorescence life time spectra also. The 1′ has two different forms in excited state with dual fluorescence emission maxima, show two monoexponential lifetimes of two different maxima with τ 1 = 4.5 ns and τ 2 = 4.7 ns due to keto‐enol tautomerism, whereas the lifetime of aluminum salts grinded form of 1′ having only one lifetime of τ > 15 ns. In solution phase sensing study, the limit of detection in water by 1′ is found 23 µM of aluminum metal ions representing its feasibility to detect aluminum ion in water. The temperature dependent emission behavior also indicates its potential toward temperature sensing as well.