Synthesis and Fluorescence Properties of α,α′-Bis(substituted-benzylidene)cycloalkanones Catalyzed by 1-Methyl-3(2-(sulfooxy)ethyl)-1H-imidazol-3-ium Chloride.

α,α′-Bis(substituted-benzylidene)cycloalkanones were synthesized via a solvent-free cross-aldol condensation of aromatic aldehydes with cycloalkanones in the presence of a catalytic amount 1-methyl-3(2-(sulfooxy)ethyl)-1H-imidazol-3-ium chloride at room temperature with excellent yields. The screening for optical properties indicated that the size of cycloalkanone has an influence on the fluorescence emission of products. Products coming from cyclohexanone have stronger fluorescence emission than those from cyclopentanone.