Using cellulose, starch and β-cyclodextrin poly/oligosaccharides as chiral inducers for preparing chiral particles

Poly/oligosaccharides are renewable natural resources with abundant chirality. Herein, we develop a general route to prepare optically active particles by using poly/oligosaccharides as both chiral inducers and growth templates. By complexing with Cu(NH3)42+ ions, OH groups on C2 and C3 in poly/oligosaccharides can transfer the chirality to Cu(II) and retain it in CuO. At the same time, poly/oligosaccharides direct growth of CuO by in situ transformation of Cu(NH3)42+ ions. Cellulose nanocrystal (CNC) and starch (ST) are used as representative polysaccharides, and β-cyclodextrin (β-CD) as a representative oligosaccharide, thus dandelion, duchesnea, and chrysanthemum-like composite particles with chiroptical activity are obtained. Besides, chiral CuO/poly(oligo)saccharide particles (CSP) demonstrate enantioselective ability by differentiating coordination with tryptophan (Trp) enantiomers and form Cu-Trp metal organic framework architectures with different morphologies. The study provides an easily accessible approach to prepare novel functional materials by poly/oligosaccharide-based chiral induction and hold great promise in chiral applications.