Synthesis and investigation of properties of pyridine substituted phthalocyanines

Due to their electrical, optical, catalytic properties, phthalocyanines have been used in many different areas such as in gas sensors, preparation of materials such as semiconductor and solar cells, in catalytic reactions and photodynamic cancer therapy. Pyridine and its derivatives have been used in many applications due to their pharmacologycal, optical and catalytic properties. Therefore, the preparation and characterization of phthalocyanines containing pyridine derivatives on periferal position would be interesting.In the present work, 5-nitropyridine disubstituted phthalonitrile 3 was prepared by the reaction of 4-dihydroxyphthalonitrile and 2-chloro-5-nitropyridine in the presence of K2CO3. 5-nitropyridine octasubstituted metal-free phthalocyanine 4 was obtained by the tetramerization of compound 3 in hydroquinone. 5-nitropyridine octasubstituted metallo phthalocyanines 5 and 6 were obtained by the reaction of compound 3 with Zn(OAc)2 or Co(OAc)2.4H2O in quinoline. 5-aminopyridine disubstituted phthalonitrile 7 was prepared by the reduction of compound 3 in the presence of 10% Pd/C catalyst. 5-aminopyridine octasubstituted metal-free phthalocyanine 8 was obtained by the tetramerization of compound 7 with metalic lithium and then its acidic hydrolysis. 5-aminopyridine octasubstituted metallo phthalocyanines 9 and 10 were obtained by the reaction of compound 7 with Zn(OAc)2 or Co(OAc)2.4H2O in the presence of DBU.Prepared compounds were characterized by 1H-NMR, 13C-NMR, UV-VIS, IR spectroscopy and elemental analysis. The aggregation behaviors of pyridine substituted phthalocyanines were studied depend on solvents and concentrations.KEY WORDS: Phthalocyanine, Pyridine, Zinc, Cobalt, Aggregation.