Tetrazines with hindered or electron withdrawing substituents: Synthesis, electrochemical and fluorescence properties

Several new s-tetrazines have been prepared with hindered, electron-withdrawing or electron-rich substituents. This is the first time that tetrazine bearing interactive functional groups other than ligands are described… Their electrochemical and spectroscopic properties have been investigated, especially concerning the electron transfer rate in the case of three selected compounds. Fluorescence occurs as expected as soon as the substituent linked to the tetrazine core is electron withdrawing enough. The existence of the tetrazine fluorescence with imide substituents might open the way to the preparation of bichomophoric fluorophores.