Experimental and theoretical observations of alkylated EOSIN based "turn-on" superoxide sensor as well as its anti-microbial study

The alkylating as well as alkoxylating behavior of dialkyl sulfites are well presented in the literature. In the present work dialkyl sulphites behavior has been investigated towards EOSIN Y (tetrabrominated fluorescein). The products of the reactions (dialkylated eosin Y) reveal that alkylation takes place at the both active sites (at hydroxyl and carboxyl functionalities) in a single step through sulphur-centred Arbuzov type rearrangement. Density functional theory (DFT) has been used as a tool to analyze the role of the halogen groups present at the periphery of the xanthene moiety in alkylation at hydroxyl and carboxy positions of EOSIN Y. Furthermore, in photo-physical study, it was observed that compound C acts as a superoxide sensor specifically with the detection limit 63 mu M. Its anti-microbial activity was checked against the E. coli and S-aureus using the agar well diffusion assay and, it was observed that it could be used as better antimicrobial agent.