Polycouplings of Alkynyl Bromides and Sulfonamides toward Poly(ynesulfonamide)s with Stable C_sp–N Bonds

The development of new polymerization methodology is crucial for polymer materials. Alkyne polymerization based on versatile reactions of C≡C bonds have attracted much attention recently because they can produce a great diversity of polymer materials with unsaturated structures and potential semiconducting properties. Among that, the polymerizations between alkyne and amine/amide which afford nitrogen-substituted alkynes with the triple bonds strongly polarized by the nitrogen atoms are quite attractive but challenging. In this work, the polycoupling of alkynyl bromides and sulfonamides is reported as the first example to generate polymers with stable N–C≡C bonds in the polymer main chain. The polycoupling of various aromatic/aliphatic alkynyl bromides and sulfonamides can be carried out at mild condition in the presence of CuSO4·5H2O, 1,10-phenanthroline, and K2CO3 at 65 °C under nitrogen, affording poly(ynesulfonamide)s with high molecular weights (up to 22 000 g/mol) in high yields (up to 95%). Incorporation of luminescent tetraphenylethene structure into the alkynyl bromide monomer can produce polymer with aggregation-induced emission property and aggregated state fluorescence quantum efficiency of 24.7%. The plentiful C≡C bonds of the polymers can serve as efficient ligands for organometallization with Co2(CO)8 to generate organometallics, which can be further pyrolyzed to afford magnetic ceramics with high magnetic susceptibility (Ms up to 80.9 emu/g) and low coercivity (Hc down to 0.008 kOe). This new polycoupling reaction provides an efficient tool for the construction of polymer materials with unique N–C≡C structures, which paves the way to advanced functionalities of polymers derived from ynesulfonamide structures.