Preparation of a photostable tribrachia cyanine dye and its high chemical activity towards hydrosulfide

Abstract The cyanine dye ( 1 ) with three arms of one chromenyl group and two indol groups was synthesized in this paper; and the proposed synthetic mechanism was also mentioned. It has excellent photostability compared to three typical cyanine dyes. Dye 1 gives high chemical activity and nearly turn-on fluorescent response towards hydrosulfide at 600–800 nm, it also has good selectivity towards hydrosulfide over other species; the detection reaction mechanism was proved by 1 H NMR analysis, and the emission responses was elucidated by time dependent density functional theory (TDDFT) calculation. The in cellular fluorescent imaging application of the dye 1 was successfully performed for the hydrosulfide imaging of HeLa cells.