Synthesis, photochemical and photophysical properties of zinc(II) and indium(III) phthalocyanines bearing fluoroalkynyl functionalized substituents

In this work, the synthesis of a novel phthalonitrile derivative with fluoroalkynyl functionalized groups and its peripherally tetrasubstituted zinc(II) and indium(III) phthalocyanine complexes were reported. The novel phthalonitrile derivative was prepared by the metal-mediated Sonogashira cross-coupling reaction between 4-iodophthalonitrile and 1-ethynyl-3,5-difluorobenzene. Metallophthalocyanines bearing fluoroalkynyl functionalized groups (compounds 3 and 4) were obtained from the corresponding phthalonitrile derivative in the presence of the corresponding metal salts in refluxing dimethylaminoethanol as the solvent. These novel compounds were characterized by elemental analyses and spectral techniques, namely FT-IR spectrometry, ¹H, ¹³C and ¹⁹F NMR spectroscopies, UV-Vis spectrophotometry, and mass spectrometry. The generation of singlet oxygen, photodegradation and fluorescence quantum yields, and fluorescence lifetime values of these complexes were determined in N,N-dimethylformamide. The effects of the substitution with fluoroalkynyl-functionalized groups on these parameters mentioned were also compared along with the previously synthesized tetrakis[(trifluoromethyl)phenylethynyl] substituted zinc(II) and indium(III) phthalocyanines.