Solvent and Guest-Driven Supramolecular Organic Frameworks Based on a Calix[4]arene-tetrol: Channels vs Molecular Cavities

Cone-shaped calix[4]arene-tetrol 3 has the ability to form open structures due to the presence of four OH groups at the upper rim, which allows the construction of H-bonded supramolecular organic frameworks (SOFs). In the presence of water, SOF-1 is formed, which contains hydrophilic channels (mean diameter of 8.5 Å) contoured by the p-phenolic OH groups. In the presence of acetonitrile, SOF-2 is formed, which contains smaller hydrophobic channels (mean diameter of 6.6 Å) delimited by aromatic walls. The Na+@3 complex, which hosts acetonitrile molecules in the calixarene cavities, and dibromo-calix[4]arene-diol 5 give rise to more compact SOFs not containing channels. The H-bond network formed by all four p-phenolic OH groups in a pinched cone conformation of the calixarene is a determinant for the porosity of SOFs based on calix[4]arene-tetrol