Preparation and optical properties of new fluorescent iminocoumarins: Study of N-acyl-derivatives

Six new iminocoumarin dyes, bearing a cyano group at the 3-position and a diethylamino group at the 7-position, were synthesized. These compounds differ by the nature of the acyl substituent borne by the imino group. They were studied in CH2Cl2 and ethanol by UV/vis absorption and fluorescence spectroscopy. This work shows that the optical properties strongly depend on the nature of the substituent borne by the imino group, and indicates which type of substituent is favourable for a given application. It confirms that iminocoumarin derivatives could lead to a new generation of fluorescent probes, prone to easy modification of their chemical structure.