Synthesis and fluorescence study of 6,7-diaminocoumarin and its imidazolo derivatives

Novel 6,7-diamino-4-methylcoumarin and derived imidazolocoumarins were synthesized and their absorption and fluorescence properties were recorded in solvents of varying polarity. 6,7-Diamino-4-methylcoumarin is highly fluorescent, with a quantum yield of 0.78 in dioxane. The fluorescence intensity of 6,7-diamino-4-methylcoumarin, when mixed with different carbonyl group containing compounds, decreased. Based on the interaction of this diaminocoumarin with the carbonyl compound a fluorescent sensor with high selectivity towards electron rich benzaldehydes and cinnamaldehyde was developed.

Graphical abstractGreen emissive diaminocoumarin on addition of benzaldehydes with electron donating groups turns to blue emissive arylimidazolocoumarin.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis of novel coumarin dyes. ► Solvent and structure dependent fluorescence. ► Selective detection of electron donating benzaldehydes and cinnamaldehyde by 6,7-diamino-4-methylcoumarin.