The UV–visible absorption and fluorescence of some substituted 1,8-naphthalimides and naphthalic anhydrides

A number of substituted 1,8-naphthalimides and naphthalic anhydrides have been prepared and their absorption and fluorescence properties in absolute ethanol have been determined. In the absence of an alkylamino substituent in the naphthalene ring, the compounds are colourless and weakly fluorescent. In the presence of such a substituent they become yellow and frequently fluoresce strongly with quantum yields of the order of 0.8.