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

Abstract

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.

Keywords:

• α,α′-Bis(substituted-benzylidene)cycloalkanones
• cross-aldol condensation
• fluorescence
• synthesis

ACKNOWLEDGMENTS

We are grateful to the National Natural Sciences Foundation of China (No. 20772103), the Natural Science Foundation in Jiangsu Province (No. BK2007028), and the Surpassing Project in Jiangsu Province (Nos. QL200607 and 08QLT001) for financial support.

Notes

^a Yield of isolated product.

^b Sodium dodecyl sulfate (SDS).

^c No reaction.

^a Reaction conditions: aromatic aldehyde (4.2 mmol) and cyclic ketone (2.0 mmol) were stirred at room temperature in the presence of I (0.10 mol%) for the given time.

^b Yield of isolated product.

^a Relative fluorescence intensity.

^b Relative fluorescence quantum yield.