Supramolecular assemblies of moroxydine hydrochloride and cucurbit[7,8]uril

Complexes of moroxydine hydrochloride (ABOB) with cucurbit[n]urils (n = 7 or 8) were investigated using 1H NMR spectroscopy, Quadrupole-Time of Flight mass spectrometry (Q-TOF), UV absorbance spectrophotometry, isothermal titration calorimetry (ITC), and X-ray crystallography. Experimental results revealed that the morpholino group of ABOB resides within the cavity of Q[7] and Q[8] respectively in both aqueous solution and solid state. In aqueous solution, 1:1 inclusion complexes of ABOB and Q[7,8] are formed with moderate binding constants. In the solid state, the cavity of Q[8] encapsulates two ABOB morpholine groups to generate a novel 2ABOB@Q[8] inclusion complex.