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 H-1 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.