Separation of Benzene and Cyclohexane by Nonporous Adaptive Crystals of a Hybrid[3]arene

The separation of benzene and cyclohexane is one of the most challenging tasks in the petrochemical field. However, conventional separation methods suffer from cumbersome operation, huge energy expenditure, or use of entrainers. Herein, we develop an environmentally friendly and energy saving adsorptive separation strategy using nonporous adaptive crystals of a hybrid[3]­arene (1). Adaptive 1 crystals separate benzene from an equimolar benzene/cyclohexane mixture with a purity of 97.5%. The selectivity comes from the stability and variability of the new crystal structure upon capture of the preferred guest, benzene. Moreover, reversible transformations between the nonporous guest-free structure and the guest-containing structure make 1 highly recyclable.