Efficient diborane-mediated synthesis of phthalocyanines carrying amino groups near the macrocycle

N-(3,4-dicyanophenyl)piperidine-2,6-dione (2) and 4-phthalimidophthalonitrile (3) were synthesized in 24% and 74% yield respectively, using 4-aminophthalonitrile as the starting material. Treatment of 2 and 3 with zinc acetate in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene gave respectively phthalocyanines 4 and 5, whose reduction with diborane afforded dyes 6 and 7. Quaternization of 6 and 7 with iodomethane gave cationic zinc(II) phthalocyanines 8 and 9 respectively. A bathochromic shift was observed in the absorption spectra when amino and ammonium groups were present near the macrocycle in comparison with those dyes carrying alkylamino and quaternary alkyl ammonium salts as peripheral substituents.

The synthesis of novel zinc(II) phthalocyanines carrying amino and ammonium groups near the macrocycle were reported. These dyes showed a bathochromic shift as compared with their peripheral substituted analogs.Figure optionsDownload as PowerPoint slideHighlights
► Novel zinc(II) phthalocyanines were synthesized.
► Cationic phthalocyanines are reported as potential mitochondrial targets.
► A bathochromic shift was observed in the absorption spectra.
► Photophysical parameters were investigated.