Copper-Catalyzed Multicomponent Polymerization of Alkynylcyclopropanes to Access Poly( N -sulfonylamidines) for Metal Ion Adsorption

Multicomponent polymerizations have experienced rapid development in recent years, enabling the conversion of diverse monomers into functional polymers through various reactive intermediates. Among these, alkylidene ketenimine has emerged as a unique intermediate exhibiting excellent reactivity in polymerization. However, its preparation has been largely limited to the usage of propargyl esters as precursors. In this work, alkynylcyclopropanes were utilized as monomers for copper-catalyzed multicomponent polymerization with di-amines and di-azides. A total of 12 poly(N-sulfonylamidines) were synthesized based on alkylidene ketenimine intermediates with molecular weights of 17,100-31,000 g/mol. The resulting polymers could be further modified by ester hydrolysis or transesterification with polyethylene glycol (PEG). Benefiting from their strong coordination ability toward metal ions, these polymers were explored as adsorbents for metal ion removal.