Revealing a nucleophilic addition reaction between aza-BODIPY and cyanide anion

In this work, a new nucleophilic addition reaction between the aza-BODIPY construct and cyanide anion is investigated and confirmed. Interestingly, CN- is verified to attack one of the pyrrole rings on the boron-dipyrromethene construct, which is different from the present CN- detection systems. The reaction mechanism is proposed based on NMR results and the photophysical spectra changes. In addition, when the electron-rich substituents are introduced to the aza-BODIPY structure, the reaction with CN- will become slow, thus confirming the nucleophilic addition reaction nature. More importantly, the mass spectra and single crystal structure of the aza-BODIPY-CN adduct could well support the proposed reaction mechanism. The reaction between CN- and aza-BODIPY is very fast (in 5 min at room temperature) and results in significant absorption and emission changes of the aza-BODIPY compound. This work, as far as we know, is the first attempt to systematically reveal the reaction between CN- and the aza-BODIPY compound. (C) 2016 Elsevier Ltd. All rights reserved.