Supramolecular Self-Assembly between Cucurbit[6]Uril and 1-(2-Hydroxyphenyl)Piperazine Hydrochloride

Abstract

The interaction between 1-(2-hydroxyphenyl)piperazine (HPP) and cucurbit[6]uril (Q[6]) has been explored via 1H NMR spectroscopy and X-ray crystallography. The results show that the guest molecule 1-(2-Hydroxyphenyl)piperazine hydrochloride is not encapsulated within the Q[6] cavity in both aqueous solution and the solid state. Instead, it resides at the portal of Q[6], forming a highly stable exclusion complex, designated HPP2@Q[6]. Notably, ion-dipole and hydrogen-bonding interactions play key roles in stabilizing this complex.

Keywords: Cucurbit[6]uril, 1-(2-Hydroxyphenyl)piperazine, hydrogen bonding interaction, ion dipole interaction, supramolecular self-assembly