Hybrid nitrate-water cluster in the hydrophobic cavity of cucurbit[8]uril

A nitrate-water cluster [(NO3)2(H2O)8]2− confined in the hydrophobic cavity of a cucurbit[8]uril complex with Sr2+ has been observed. It represents the first example of inorganic anion-water cluster formation inside the cucurbit[n]uril hydrophobic cavity.