Abstract

Anthraquinone is a natural dye with many applications. The present findings provide valuable information on the photophysical properties of natural anthraquinone, which are previously inaccessible due to unavailability/difficulty in obtaining pure samples. The absorption/emission bands were found to have shifted to the visible region, as a result of hyper-conjugation phenomenon due to the formation of additional quasi aromatic rings between the strategically located substitution groups with the anthraquinone core structure. The formation of the quasi aromatic rings was supported by the observation in the NMR spectra. The results suggested the role of the substitution group in controlling absorption/emission band transitions and selectivity, highlighting anthraquinone potential in the dye and sensor applications.