A long-standing problem in cucurbituril chemistry is answered through the first direct functionalization of cucurbit[n]uril (CB[n]; n = 5-8)) leading to perhydroxyCB[n] which can be further modified to provide tailored CB[n] derivatives with desired functional groups and good solubility. Anchoring a CB[6] derivative on the surface and its potential application as a sensor are demonstrated. A CB[6] derivative forms nanospheres with possible use in protein and peptide drug delivery.

The [2 + 2] photoreaction of (E)-diaminostilbene dihydrochloride proceeds with large rate acceleration and high stereoselectivity via formation of a stable 1:2 host-guest complex with curcurbit[8]uril in solution.

Machinelike behavior—reversible dethreading and rethreading of a molecular bead—is demonstrated in a self‐assembled monolayer (SAM) of a pseudorotaxane on gold. Furthermore, unprecedented ion‐gating behavior associated with threading and dethreading is observed; the SAM blocks or allows the access of electroactive species to the electrode surface depending on the presence or absence of the threaded molecular bead (see picture).

Ion selective electrodes (ISE) based on three different tripodal receptors (5, 6, and 7) have been investigated for sensing ammonium ion. Each receptor is based on three pyrazole groups that can accept three H-bonds from the bound ammonium ion. The receptor based on 4-bromo-3,5-dimethylpyrazole (6) is the most sensitive with a detection limit for ammonium ion of 2.5 x 10(-5) M at pH 8. The detection limits for the receptors based on 2,3-dimethylpyrazole (5) and unsubstitued pyrazole (7) are 1.0 x 10(-4) and 2.0 x 10(-4) M, respectively. The selectivities of the receptors 5, 6, and 7 for sensing ammonium ion over potassium ion (logK(NH)4+(/K)+) are -2.8, -2.3, and -1.7, respectively. In contrast, the detection limit and the selectivity of a nonactin-based ISE are 2.2 x 10(-5) M and -1.3, respectively. Crystallographic studies reveal that 6 accepts three H-bonds from the bound ammonium and singly protonated receptor 5 forms three H-bonds with the bound water molecule.