Synthesis and characterization of novel tetra terminal alkynyl-substituted phthalocyanines and their star polymers via click reaction

Abstract

Abstract For the first time, symmetrically tetra terminal alkynyl-substituted phthalocyanines (Pcs) were functionalized with polymers, that is, via 1,3-dipolar cycloaddition reaction. For this purpose, 4-pent-4-ynyloxy-phthalonitrile ( 3 ) was prepared by the nucleophilic displacement reaction of 4-nitrophthalonitrile ( 1 ) and 4-pentyne-1-ol ( 2 ). The syntheses of the target 2,9(10),16(17),23(24)-tetra terminal alkynyl-substituted phthalocyanines ( 4 – 6 ) were achieved with reasonable yields by a direct cyclotetramerization reaction in the presence of zinc acetate, cobalt acetate, and/or DBU in pentanol without protection/deprotection. Successful ‘click’ reactions between well defined azido-terminated polystyrene (PS-N 3 ) ( 7 ) or poly( tert -butyl acrylate) (P t BA-N 3 ) ( 8 ) and alkynyl-terminated phthalocyanines ( 4, 5 ) yielded four arm star polymers. The precursors and the target star polymers were characterized comprehensively by 1 H NMR, 13 C NMR, FT-IR, UV–Vis, GPC and elemental analysis.