Polyether-bridged cyclophanes incorporating bisphenol A units as neutral receptors for quats: synthesis, molecular structure and binding properties

Two novel neutral polyoxyethylene bridged cyclophanes (2a and 2b) incorpora ting bisphenol A units were synthesized and characterized by means of x-ray crystal structure determination. The binding properties of 2a and 2b towar d tetramethylammonium, N-methylpyridinium, and acetylcholine cations were e valuated by means of H-1 NMR spectroscopy. Consistent with indications prov ided by the molecular structure, the cavity in the basket-like cyclophanes is large enough to accommodate the given guest cations conveniently. Circum stantial evidence was obtained that 1,1,2,2-tetrachloroethane is too large to enter the cavity of the smaller cyclophane 2a, but can be included in th e cavity of the larger cyclophane 2b. Copyright (C) 2001 John Wiley & Sons, Ltd.