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 systems were characterized by 1 H, 13 C, and 31 P 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 emission spectroscopy. In these derivatives, the bino-type cyclotriphosphazene derivative bearing unsubstituted BODIPY unit 4 P exhibited high fluorescence and no singlet oxygen generation due to the lack of spin converter. The attachment of heavy atoms (iodine and bromine) enabled the production of singlet oxygen. The bino-type BODIPY-cyclotriphosphazenes (5P and 6P) were also used as triplet photosensitizers in the photooxidation of 1,3-diphenylisobenzofuran to endoperoxide via generation of the singlet oxygen in dichloromethane. The singlet oxygen production of these compounds was also investigated via a direct method and produced a singlet oxygen phosphorescence peak at 1270 nm.

Synthesis, characterization, photophysical, and photochemical studies of BODIPY derivatives

“…Starting by the preparation of aldehyde derivatives ( 2 , 4 , and 7 ), BODIPY cores ( 8–10 ) were obtained by following the standard protocol. 27,29,35 Later, BODIPYs 8–10 were reacted with iodine in ethanol to synthesize the diiodo-BODIPY derivatives 11–13 . Functionalization of the BODIPYs on the 2- and 6-positions with iodine provided a heavy atom effect for the spin conversion that was necessary for the triplet excited state formation.…”

“…Starting by the preparation of aldehyde derivatives (2, 4, and 7), BODIPY cores (8-10) were obtained by following the standard protocol. 27,29,35 Later, BODIPYs 8-10…”