Spontaneous Capture of Carbohydrate Guests through Folding and Zipping of Self-Assembled Ribbons

Abstract

One of the great challenges in molecular self-assembly is how to confer self-folding and closing characteristics on flat two-dimensional structures in response to external triggers. Herein, we report a planar ribbon assembly that folds into closed tubules in response to fructose. The ribbons, ≈28 nm wide and 3.5 nm thick, consist of 8 laterally-associated elementary fibrils in which disc-shaped macrocycle amphiphiles are stacked along their axis. Upon addition of fructose, these flat structures spontaneously fold into closed tubules, with an outer diameter of ≈8 nm, through zipping of the two sides of the ribbons. Notably, the folding and then zipping of the flat ribbons is accompanied by spontaneous capture of the fructose molecules inside the tubular cavities.

Keywords: carbohydrate capture; lengthwise folding; ribbon structure; self-assembly; zipping.