Per(6-amino-2-O-carboxymethyl-6-deoxy-3-O-methyl)-α-cyclodextrin: Helical Self-Assembly of a Polyionic Amino Acid into Nanotubes

A zwitterionic α-cyclodextrin amino acid (picture, middle) undergoes solid-state self-assembly to give a novel helical column architecture (left), which is cross-linked by hydrogen bonds into an array of parallel straight channels (right). Surprisingly, no hydrogen bonds are formed between proximate cyclodextrin units in the individual channels.