Halide-Anion Water Clusters in Cucurbit[6]uril Supramolecular Systems

Three types of dihalide water clusters [X2（H20）8]2 （X=Cl, Br） and [I2（H20）10]^2- have been observed in cucurbit[6]uril supramolecular systems with same guest. According to the single crystal data and the quantitative theory computation, with the increase of electronegativity of halide ions, dihalide water clusters become more stable. A further comparison of three kinds of guests with different molecule length but the same anions, [p-phenylenediamine salt, hexamethylenediamine salt and N,N＇-hexamethylenebis（pyrazinylbromide）], gives the result that the dihalide water clusters collapse from 2D to 1D with the increase of the lengths.