Oligothienyl-BODIPYs: Red and Near-Infrared Emitters

The synthesis of unsymmetrical 3,5-dioligothienyl-BODIPY derivatives and their optical and redox properties are reported. The key step is the monobromination of the 2,6-dimethyl-3,5-dithienyl-BODIPY at the a position of the thiophene moiety. The additional thiophene modules are attached by palladium-catalyzed cross-coupling reactions. Increasing the number of modules on each side of the BODIPY core progressively shifts the absorption to 677 nm and the emission to 769 nm.