Constructing Near-Infrared Dyes with D-A-D Type Stark Shifts Based on Asymmetric Electron Donating Properties and their Applications

Abstract

The excessive amount of SO2 poses a threat to the microenvironment of living organisms and in severe cases can cause diseases such as inflammation, cardiovascular diseases and respiratory damage. As one of the important atmospheric pollutants, sulfur dioxide and its derivatives are widely used in the production of additives and chemicals, as well as being one of the important factors affecting physiological activities. To achieve the goal of detection, we have developed a new near-infrared fluorescent probe Cou-Oxo, which can be used to ratiometric SO2 derivatives in cells, zebrafish, and plant rhizomes. A novel near-infrared dye with a large π-system has been created by combining two small π-dyes. The dye Stokes shifts across was also expand by its structure (321 nm). The NIR ratiometric fluorescence properties of the probe are achieved through the addition reaction of SO2 derivatives (HSO3-) to the C=C double bond on the Cou-Oxo probe. It has a detection line of 0.942 μM, a short response time (within 30 s), good biocompatibility, excellent anti-interference, and pH stability. The probe was successfully used to detect changes in exogenous/endogenous SO2 levels in cancer cells and living zebrafish. More interestingly, we successfully accomplished the visualization of SO2 in normal and SO2-poisoned seedlings using tobacco seedlings as a model.