The cucurbit[7]uril effect on reference substances for NMR in deuterium oxide solution

The effect of macrocyclic molecule cucurubit[7]uril on the chemical shifts of internal reference substances for NMR studies in deuterium oxide solution and the cause were investigated.

Selective recognition and determination of phenylalanine by a fluorescent probe based on cucurbit[8]uril and palmatine

This paper demonstrated a simple and validated fluorescence enhancing method to selectively recognize and discriminate the amino acid phenylalanine (Phe). ¹H NMR spectroscopy reveal that the palmatine (PAL) can be encapsulated into the cucurbit [8]uril (Q [8]) in aqueous solution to form stable 1:2 host-guest inclusion complex PAL₂@Q [8], which exhibits moderate intensity fluorescence property. Interestingly, the addition of the Phe into the inclusion complex PAL₂@Q [8] leads to dramatically enhancing of the fluorescence intensity. In contrast, the addition of any other natural amino acids into the inclusion complex PAL₂@Q [8] gives no fluorescence variation. Furthermore, it is easy to detect the concentration of Phe in target aqueous solution according to the linear relationship between fluorescence intensity and concentration of the Phe.