Novel BODIPY-bridged cyclotriphosphazenes

Abstract

Three new 2-component unsubstituted (4P), diiodo- (5P), and dibromo- (6P) distyryl-BODIPY-bridged cyclotriphosphazene dimers were designed and synthesized. The newly synthesized BODIPY-cyclotriphosphazene systemswere characterized by 1 H, 13 C, and 31P NMR spectroscopy. The photophysical properties of the distryl-BODIPYs(4–6) and BODIPY-cyclotriphosphazene dyads (4P–6P) were studied by UV-Vis absorption and fluorescence emissionspectroscopy. In these derivatives, the bino-type cyclotriphosphazene derivative bearing unsubstituted BODIPY unit 4P exhibited high fluorescence and no singlet oxygen generation due to the lack of spin converter. The attachment of heavyatoms (iodine and bromine) enabled the production of singlet oxygen. The bino-type BODIPY-cyclotriphosphazenes (5Pand 6P) were also used as triplet photosensitizers in the photooxidation of 1,3-diphenylisobenzofuran to endoperoxidevia generation of the singlet oxygen in dichloromethane. The singlet oxygen production of these compounds was alsoinvestigated via a direct method and produced a singlet oxygen phosphorescence peak at 1270 nm.