Isostructural, Alternately‐Charged Receptor Stacks. The Inclusion Complexes of Hydroquinone and Catechol Dimethyl Ethers with Cyclobis(paraquat‐ p ‐phenylene)

The salt 1ṁ4PF 6 ·3CH 3 CN is a new type of host molecule , which shows similarities to zeolites but is constructed from organic and inorganic ions. The macrocyclic tetracation 1 can be prepared in two steps from bipyridine and 1,4‐bis(bromomethyl)benzene. Calculations and X‐ray crystallography showed the tetracation to have a box‐like structure in which the p ‐phenylene and paraquat units are slightly bent. The PF   6 ⊖ ‐salt of 1 is soluble in organic solvents, the Cl ⊖ salt in water. 1 ·4PF 6 in acetonitrile forms weak inclusion complexes with dimethoxybenzenes, which are stabilized by charge‐transfer interactions. Structural studies of the inclusion complexes show that the electron‐rich guest molecules are located in the cavities ( 2 ); because of the stapling of the alternating tetraction and anion/neutral molecule layers these cavities take the form of channels.