Unmetallated and metallated phthalocyanines bearing oxadiazole groups: Synthesis, photophysical and photochemical studies

Unmetallated (4) and metallated (zinc(II), cobalt(II), lead(II)) phthalocyanines (5-7) carrying four 4-(4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenoxy) groups on the peripheral positions were synthesized by cyclotetramerization of 4-(4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenoxy)phthalonitrile (3) in the presence of corresponding metal salts (zinc(II) acetate, cobalt(II) chloride, lead(II) oxide) for metallated and without any metal for unmetallated phthalocyanines. The obtained organo-soluble phthalocyanines were characterized by infrared, electronic absorption, nuclear magnetic resonance and mass spectral techniques and elemental analysis as well. The photophysical and photochemical properties of newly synthesized tetra-substituted unmetallated (4), zinc(II) (5) and lead(II) (7) phthalocyanines were reported in N,N-dimetilformamid (DMF). The synthesized phthalocyanine compound 6 was not evaluated for photophysical and photochemical studies due to open shell and paramagnetic behavior of cobalt(II) metal ions in the phthalocyanine cavity.