Ratiometric fluorescent detection of temperature and MnO4- using a modified covalent organic framework

A new covalent organic framework (COF), PP-TzDa, has been synthesized by post-synthetic modification. Our studies suggest that the modification leads to the changes of both the stacking mode and the fluorescence emission. This new COF shows dual fluorescence emissions, and can be used as a ratiometric fluorescent temperature sensor. In the range of 20–100 °C, the COF suspensions in DMF exhibit the temperature dependent fluorescence and the intensity ratios of two emissions change linearly with temperature. The new COF can also be used as a ratiometric fluorescent sensor for MnO4-. This work represents the opportunity to tune their fluorescent properties and explore their applications of a variety of COFs by simple modification.