Postpolymerization modification based on dynamic imine chemistry for the synthesis of functional polyacetylenes

We report here a postpolymerization modification approach based on dynamic imine chemistry for the facile synthesis of a variety of functional polyacetylenes from a polymeric substrate. A high molecular weight polyacetylene bearing imine moiety (P1) was synthesized and used as the parent polymer. Postpolymerization modification of P1 with a series of amines, (S)- and (R)-1-phenylethanamine, (S)-2-amino-2-phenylethanol, (S)-1-(naphthalen-2-yl)ethanamine, and 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl through transimination afforded the target products (P1a–P1e). Transimination reactions proceeded smoothly under mild conditions without any catalysts, and complete substitution was confirmed under suitable conditions by 1H NMR spectroscopy. Incorporation of chiral pendant groups induced predominantly one-handed helicity along the polyene backbone (P1a–P1d). P1e formed from 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl exhibited reversible charge/discharge ability, indicative of its capacity as an electrode-active material for organic batteries. Given the commercial availability of diverse amines and mild reaction conditions, the transimination reaction is considered as a versatile polymer modification tool for the preparation of functional materials.