Cyclodextrin–calixarene co-polymers as a new class of nanosponges

Hyper-reticulated co-polymers jointly formed by cyclodextrin and calixarene units, which can be considered as a new class of nanosponges, were easily obtained by means of a click chemistry approach. In particular, we succeeded in preparing our materials by exploiting the copper-catalyzed 1,3-dipolar cycloaddition (CuAAC) reaction between heptakis-(6-deoxy)-(6-azido)-β-cyclodextrin and (5,11,17,23-tetra-tert-butyl)-(25,26,27,28-tetra-propargyloxy)-calix-[4]-arene, mixed in different proportions. These materials were fully characterized by means of combined FT-IR, thermogravimetric, 13C {1H} CP-MAS NMR and nitrogen adsorption/desorption techniques. In particular, 13C {1H} CP-MAS spectra allowed us to perform a quantitative analysis of the co-polymers obtained. Tests on their possible sequestering abilities towards some organic molecules, in particular nitroarenes and commercial dyes chosen as suitable pollutants or drug models, were successfully carried out. Results obtained point out that absorption abilities seem affected by polymer composition and porosity as well.