Benzyl ether type of dendronized carbohydrates: Synthesis and liquid crystallinity

Most of traditional carbohydrate liquid crystals are composed of sugar moiety substituted by n-alkyl chains.There are still quite limited categories in this liquid crystal library.In this study,dendronized carbohydrate liquid crystals were synthesized with N-acetylglucosamine as core unit,and wedge or taper shaped benzyl ether type dendrons as branches.Liquid crystallinity of dendronized carbohydrates was studied by POM,DSC,XRD,CD/UV spectroscopy.Molecules contain wedge shaped dendrons can self-organize into chiral columnar hexagonal phase or achiral nematic phase,while molecules contain taper shaped dendrons still self-organize into chiral columnar hexagonal phase,not however cubic phase as suspected.Supramolecular chirality is most probably derived from a helical arrangement of dendrimers around the cylinder axis,driven by a collaborative self-assembly of carbohydrate core and dendron branches,and the chiral carbohydrate center plays the primary role of selecting the handedness of the helix so as not to be racemization.This novel dendronized carbohydrate liquid crystal may provide inspiration in the study of chiral supramolecular aggregates induced by carbohydrates.