A New Functional Cyclophane Host. Synthesis, Complex Formation and Crystal Structures of Three Inclusion Compounds

A new macrocyclic host compound 2 having an octamethyl substituted cyclophane structure with two intra-annular carboxylic acid functions has been synthesized. The properties of crystalline inclusion formation are studied and X-ray crystal structures of three inclusion complexes including acetic acid, propionic acid and acetone as the guest molecules are reported. Inter-host channel formation with complexed guest molecules accommodated into the channels are typical features of the acetic acid and acetone 1 : 4 (host : guest) stoichiometric complexes being also hydrated species, while the propionic acid 1 : 2 complex is of the close packing type containing no additional water molecules. Systems of hydrogen bonds involving the host and guest functional groups are common to all structures. In the case of the acetic acid inclusion compound, a complex supramolecular hydrogen-bonded array comprising a bordering tricyclic assembly of eight molecular species exists.