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

• 4-pent-4-ynyloxy-phthalonitrile is synthesized as a new precursor.
• Cyclotetramerizations resulted tetra terminal alkyne-substituted phthalocyanines.
• Click reaction between Pcs and azido-PS and PtBA yielded star polymers with Pc core.

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-N3) (7) or poly(tert-butyl acrylate) (PtBA-N3) (8) and alkynyl-terminated phthalocyanines (4, 5) yielded four arm star polymers. The precursors and the target star polymers were characterized comprehensively by 1H NMR, 13C NMR, FT-IR, UV–Vis, GPC and elemental analysis.

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