Novel highly soluble fluoro, chloro, bromo-phenoxy-phenoxy substituted zinc phthalocyanines; synthesis, characterization and photophysicochemical properties

• Synthesis of novel zinc phthalocyanines bearing different halogen atoms bonded phenoxy-phenoxy moiety.
• The substituent and solvent effects on the photophysicochemical parameters of Pcs.
• Photodynamic therapy studies.

The three new phthalocyanine precursors, 4-[4-(bromo phenoxy)phenoxy]phthalonitrile, 4-[4-(chlorophenoxy)phenoxy]phthalonitrile, 4-[4-(flourophenoxy)phenoxy]phthalonitrile (1, 2 and 3) were synthesized and characterized. The photochemical properties (singlet oxygen quantum yields and photodegradation quantum yields) and photophysical properties (fluorescence quantum yields and fluorescence behavior) of their peripherally tetra substituted zinc phthalocyanines (4)-tetra[bromo phenoxy]phthalocyaninato zinc(II), (4)-tetra[chlorophenoxy]phthalocyaninato zinc(II), (4)-Tetra [flourophenoxy]phthalocyaninato zinc(II) (4, 5 and 6) were reported for the first time. The new compounds (1–6) were characterized by using spectroscopic methods, FT-IR, 1H NMR spectroscopy, electronic spectroscopy and mass spectra as well as elemental analysis. General trends focus on fluorescence, photodegradation and singlet oxygen quantum yields of these compounds in dimethylsulfoxide (DMSO), dimethylformamide (DMF) and tetrahydrofuran (THF). The nature of the substituent and solvent effects on the photophysical and photochemical parameters of the chloro, fluoro, bromo-phenoxy-phenoxy substituted phthalocyanines (4, 5 and 6) was also reported.

In the present study, we describe the synthesis and characterization and photophysical and photochemical properties of highly soluble zinc phthalocyanines (4, 5 and 6). Synthesized phthalocyanines showed good photochemical properties such as high singlet oxygen quantum yields. A typical spectrum for the determination of singlet oxygen quantum yield of complex 4 in DMF at a concentration at 6 × 10−6 mol dm−3.Figure optionsDownload as PowerPoint slide