First synthesis and electronic properties of cyano(oligo)phenothiazines

Abstract (Oligo)phenothiazinyl nitriles were synthesized in good to very good yields from bromo (oligo)phenothiazines via the Beller cyanation protocol either under conductive or under dielectric heating using NMP as a solvent. Their electronic properties were determined by absorption and emission spectroscopy and cyclic voltammetry. Cyano(oligo)phenothiazines display large Stokes-shifts (5800–8300 cm −1 ) and substantial quantum yields (11–27%). Their reversible oxidation potentials are considerably shifted anodically due to the electron-withdrawing character of the cyano group.