Novel phthalocyanine–BODIPY conjugates and their photophysical and photochemical properties

Abstract

Novel zinc(II) phthalocyanines bearing boron dipyrromethene (BODIPY) (8) and its mono-styryl (9) and di-styryl (10) derivatives containing p-(N,N-diethylamino)benzaldehyde moieties were designed and synthesized for the first time. These phthalocyanines (8–10) were prepared by the copper-free Sonogashira coupling reaction of terminal ethynyl functionalized BODIPYs [4,4′-difluoro-8-(4-propynyloxy)-phenyl-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (2), 4,4′-difluoro-8-(4-propynyloxy)-phenyl-3,5,7-trimethyl-1-((4-diethylaminophenyl)ethenyl)-4-bora-3a,4a-diaza-s-indacene (5), or 4,4′-difluoro-8-(4-propynyloxy)-phenyl-3,5-dimethyl-1,7-bis((4-4″-diethylaminophenyl)ethenyl)-4-bora-3a,4a-diaza-s-indacene (6)] with tetrakis(iodo) zinc(II) phthalocyanine (7). All newly synthesized compounds were fully characterized by elemental analysis and general spectroscopic methods such as 1H NMR, FT-IR, mass, UV–Vis, and fluorescence. The photophysical (fluorescence quantum yields and lifetimes), photochemical (singlet oxygen generation capability and photodegradation behaviors) properties of these phthalocyanines were also investigated for determination of their photodynamic therapy (PDT). The results obtained indicated that these conjugates could be promising photosensitizers for PDT applications.