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

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-ynyloxyphthalonitrile (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(tertbutyl acrylate) (PtBA-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 H-1 NMR, C-13 NMR, FT-IR, UV-Vis, GPC and elemental analysis. (C) 2013 Elsevier Ltd. All rights reserved.