Synthesis and photophysics of new metallo phthalocyanine complexes with thiazole groups and their fluorescence quenching studies with benzoquinone

The synthesis of novel, symmetrical, tetra substituted metallo- phthalocyanines (cobalt, zinc and copper) bearing four 2-(4-methyl-1,3-thiazol- 5-yl)ethoxy units was reported. The reaction of 2-(4-methyl-1,3-thiazol-5-yl) ethanol with 4-nitrophthalonitrile in the presence of K₂CO ₃ led to formation of 4-[2-(4-methyl-1,3-thiazol-5-yl)ethoxy] phthalonitrile. Co and Zn phthalocyanines were synthesized using microwave irradiation from the corresponding phthalonitrile compound and metal salts (CoCl₂ and Zn(CH₃COO)₂) in hexanol in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Cu phthalocyanine was obtained by heating the phthalonitrile derivative and copper (II) chloride at 160 C in n-hexanol in the presence of DBU. The resulting products were purified by column chromatography and characterized by several chemical and spectroscopic analysis methods. Photophysical properties with zinc (II) phthalocyanine were found, including electronic absorption and fluorescence quantum yield. The fluorescence of the complexes was investigated in DMF and it was found that benzoquinone (BQ) was an effective quencher.