Helical poly(phenyl isocyanide)s grafted selectively on C-6 of cellulose for improved chiral recognition ability

Cellulose graft copolymers are an effective way to endow new properties to cellulose substrate, as well the rigidity, regularity, and helicity of the cellulose backbone could induce the self-assembly of supramolecular structures. In this work, right-handed helical poly(phenyl isocyanide)s (PPI n ) were grafted selectively onto C-6-cellulose. Alkyne-terminated PPI n was synthesized by living polymerization of right-handed phenyl isocyanide monomer using an alkyne-terminated palladium(II) complex as an initiator/catalyst, and were grafted onto the C-6 of the cellulose backbone (Cell-6-g-PPI n ) at various chain lengths using copper-catalyzed alkyne-azide cycloaddition (CuAAC) “click” chemistry. We confirmed the successful grafting by liquid 1 H NMR and 13 C NMR, as well as solid 13 C NMR, FTIR, and GPC. After grafting onto cellulose, the right-handed chirality of PPI n was significantly increased by 111.2%. Additionally, the Cell-6-g-PPI n exhibited better chiral recognition of L-Phe-DNSP than PPI n alone. Therefore, the helical cellulose backbone has enhanced effect on preferred helix of PPI n .