Host-guest properties of pagoda[4]arene with a,u-dibromoalkanes and their self-assembled linear supramolecular polymer driven by guest halogen-halogen interactions

Herein we report the host-guest interactions of pagoda[4]arene with various a,u-dibromoalkanes. The guest encapsulation properties were probed by 1H NMR titration and isothermal titration calorimetry (ITC) experiments. Unlike pillararenes, the deeper cavity of pagoda[4]arene shows higher affinity toward longer straight-chain molecules with 1:1 host-to-guest stochiometric ratio of complexation. In addition, the formation of the self-assembled supramolecular polymer driven by guest halogen-halogen in-teractions in solution was demonstrated by diffusion-ordered spectroscopy (DOSY), ITC, and dynamic light scattering (DLS) measurements. From the ITC dilution experiments, we found that the supramo-lecular polymer dissociation process is mainly entropically driven (TDS = 64.00 kJ mol-1) and enthalpically disfavored (DH = 43.91 kJ mol-1).(c) 2023 Elsevier Ltd. All rights reserved.

Automated summary

In this study, the host-guest interactions between pagoda[4]arene and various a,u-dibromoalkanes were investigated. The encapsulation properties of the guest were examined using 1H NMR titration and isothermal titration calorimetry (ITC) experiments. Unlike pillararenes, pagoda[4]arene exhibited a higher affinity towards longer straight-chain molecules with a 1:1 host-to-guest stoichiometric ratio of complexation. Additionally, the formation of a self-assembled supramolecular polymer driven by guest halogen-halogen interactions in solution was demonstrated through diffusion-ordered spectroscopy (DOSY), ITC, and dynamic light scattering (DLS) measurements. The ITC dilution experiments revealed that the dissociation process of the supramolecular polymer was mainly driven by entropy (TDS = 64.00 kJ mol-1) and disfavored by enthalpy (DH = 43.91 kJ mol-1).(c) 2023 Elsevier Ltd. All rights reserved.