Secondary assembly mechanism of cyclodextrin based on LiNTf2@β-CD system

Cyclodextrin-based nanotubes have been widely investigated and their secondary assembly (SA) behavior was found in our previous works. Here we report the self-assembly behavior between lithium bis(trifluoromethylsulfonyl)imide (LiNTf2) and beta-cyclodextrin (beta-CD). Nanosheet structures with regular shape were obtained in the concentrated LiNTf2@beta-CD solution. This phenomenon can be explained in terms of the SA mechanism of CD induced by the inorganic guest LiNTf2. LiNTf2 and beta-CD firstly forms nanotubes, and the nanotubes further stack with each other to form nanosheets by SA. We confirm that the hydrogen-bonding interaction contributes a lot to the formation of the nanotubes and their SA, and Li+ shows a special effect in the SA by inducing hydrogen-bonding network between the adjacent beta-CD to regularly pack the nanotubes.