Engineering Void Space Enclosed within Resorcin[4]arene-Based Supramolecular Frameworks

A family of hydrogen-bonded supramolecular frameworks based on C-alkylresorcinol[4]arene (RsC) and 4,4'-bipyridine (bpy) type spacers are described in this article. The size and shape of the void space enclosed within these frameworks are engineered by varying the type of trans-1,2-bis (4-pyridyl)ethylene (bpe), 1,2-bis(4-pyridyl)acetylene (bpa)) and the conformations and/or type of RsC bowl (boat vs cone of C-methylresorcin[4]arene/RsC1 vs C-propylresorcin[4]arene/RsC3). A change in the solvent system from acetonitrile to ethanol brings about a conformational change with the RsC1 macrocycle and also results in the distinct orientation of spacer molecules around the RsC macrocycle. The predominant feature in all of the frameworks is the O-H center dot center dot center dot N intermolecular interaction between RsC buliding blocks and bipyridine-type spacers. The resultant solvent-filled void spaces available within frameworks can be controlled by manipulating the parameters investigated in this study.