BODIPY quaternary ammonium salt as photosensitizers

Using 4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene as starting material, N,N,N-trimethyl-2-(4,4-difluoro-4-bora-3a,4a-diaza-s-indacen-8-yl)ethylammonium iodide (BODIPY quaternary ammonium 17) was successfully synthesized. While this BODIPY ammonium was found to be less stable than Rose Bengal both in light and dark, it showed a superior efficiency as a photosensitizer, leading to the photodegradation of 1,3-diphenylisobenzofuran at a rate about 2.6 times faster than Rose Bengal. Supplementation of this BODIPY in agar cultures did not show antibacterial activity against Escherichia coli DE3 exposed to light, however, inclusion of 5 μM BODIPY 17 in agar plates led to complete killing to Bacillus subtilis while exposed to light.