Host‐Guest Inclusion Complexes of Geraniol and Nerol with Acyclic Cucurbit[n]urils: Preparation, Characterization and Controlled Release

Abstract

Two main components of rose essential oil, geraniol and nerol are highly volatile, and hardly water‐soluble, which limit their further development and application in food and cosmetics industry. Host‐guest inclusion complexation could be a promising strategy to address these issues. Herein, new inclusion systems of geraniol and nerol with two acyclic cucurbit[n]urils (ACBs) were fabricated, and their binding behaviors both in solution and solid states were investigated by fluorescence spectroscopy, NMR, XRD, FT‐IR spectroscopy and TGA. The results confirmed the formation of host‐guest inclusion complexes. The stoichiometry of the complexes was proved to be 1 : 1 by Job's plot. The possible inclusion modes were proposed by 2D‐ROESY experiments. The pH‐dependent release of guest molecules from the inclusion complexes has been studied via UV‐Vis spectroscopy. The heat‐controlled release properties of guest molecules from the solid inclusion complexes were studied via 1H NMR spectra. The complexes featured less volatilization under low temperature, longer retention time, better water solubility and improved heat‐controlled release properties. In brief, this work uncloses a new strategy to enhance the performance of essential oils and flavors/fragrances and further their application in the field of cosmetic and food industry.

Rapid Classification and Recognition Method of the Species and Chemotypes of Essential Oils by ATR-FTIR Spectroscopy Coupled with Chemometrics

“…The spectra of CM-EOs were mainly characterized by the signals of geraniol. In particular, the peaks at 3325, 1669, 1233, and 998 cm −1 were induced by the primary O−H stretch, C=C stretch, C−C stretch and C−O stretch, respectively [ 41 ]. Additionally, the small signal at 1728 cm −1 was assigned to the carbonylic stretch of geranyl acetate.…”