Novel rhodamine dye with large Stokes shifts by fusing the 1,4-diethylpiperazine moiety and its applications in fast detection of Cu.

Rhodamine dyes were widely developed for designing probes due to their excellent photophysical properties and biocompatibility. However, traditional rhodamine dyes still bear major drawbacks of short emission wavelengths (<600 nm) and narrow Stokes shifts (<30 nm), which limit their biological imaging applications. Herein, we reported a novel mitochondria-targeted fluorescent dye JRQ with near-infrared (NIR) emission wavelength and improved Stokes shift (63 nm) by tuning the donor-acceptor-donor (D-A-D) character of the rhodamine skeleton.

A near-infrared fluorescent probe with an improved Stokes shift achieved by tuning the donor-acceptor-donor character of the rhodamine skeleton and its applications.

In this paper, we report a novel near-infrared (NIR) mitochondrion-targeted fluorescent probe, RQS, with an improved Stokes shift (96 nm) for the specific detection of mitochondrial mercury ion (Hg) because mitochondrion is one of the main targeted organelles of Hg. For the preparation of the probe, a novel asymmetrical fluorescent xanthene dye RQ was first synthesized by tuning the donor-acceptor-donor (D-A-D) character of the rhodamine skeleton, and then the probe RQS was constructed by the mechanism of mercury-promoted ring-opening reaction. As expected, RQS could be used for the specific detection of Hg with high selectivity, high sensitivity, and a detection limit down to the nanomolar range (2 nM).