A new unsymmetrical phthalocyanine with a single o-carborane substituent

Unsymmetrical zinc phthalocyanine carrying a single o-carborane substituent on the peripheral position was synthesized in a multistep reaction sequence. At the first step, metal-free phthalocyanine 3 was prepared by cyclotetramerization of 4,5-di(hexylthio)phthalonitrile and 4-(2-hydroxyethylthio)phthalonitrile in pentanol in the presence of lithium; and zinc phthalocyanine 4 was prepared by insertion of Zn(II) salt. After esterification of phthalocyanine 4 with 4-pentynoic acid, terminal alkynyl bearing precursor phthalocyanine 5 was obtained. At the last step, reaction of decaborane with phthalocyanine 5 yielded phthalocyanine 6 with the desired o-carborane moiety. The new phthalocyanine compounds were characterized by elemental analysis, NMR, FT-IR, UV-vis and mass spectral data. Aggregation behaviour and electrochemical properties of these newly synthesized unsymmetrical phthalocyanine derivatives were also reported.