Separation of closely related structural isomers by inclusion complexation with tailor-made host compounds. Crystal structures of 2,2-di (p-hydroxyphenyl) propane and Its 1:1 complex with p-cresol

The crystal structures of the 2,2-di(p-hydroxyphenyl)propane host and its 1:1 adducts with m-and p-cresol guests have been studied. The preferential complexation of this host with p-cresol over m-cresol is related to the opposite trend exhibited by 1,1-di(p-hydroxyphenyl)cyclohexane; both hosts can separate effectively the two cresols from their liquid mixture by crystalline inclusion. A plausible explanation of the different inclusion features is provided by examining the intermolecular association in the corresponding solids. The analysed structures are stabilized by strong and continuous H-bonding between the constituent entities along two dimensions, and by weak van der Waals forces along the third axis. The p-cresol complex of the title host reveals a unique arrangement within and a more efficient packing of the layered structure, and thus represents a more stable and less soluble crystal lattice than its m-cresol analog.