Institute of Applied Chemistry, Faculty of Chemistry,
Cucurbiturils are cage-like organic compounds (CB[n]), which can be synthesized by condensation of glycoluril and formic aldehyde. There are n of glycolurils linked by methylene bridge in molecular structure of CB[n]. CB[n] can include small molecule in its inner space to make supramolecular inclusion compounds, which can be used as catalyst, molecular device, sensor, drug delivery system and biomimetics.
Linalool (LIN) is one of main components of essential oils from some fragrant plants, which is used as an antimicrobial additive for food preservation and a natural insecticide. LIN is a terpene phenol and its chemical name is 3,7-dimethyl-1,6-octadiene-3-ol (C10H18O). Derivatives and hybrid materials of LIN with carrier or capsule were prepared to decrease such side effects and increase its function.
Researchers have studied on electronic structure and stability of inclusion compounds (LIN@CB[n]) of LIN and CB[n] (n=5~8) by DFT.
Initial geometric structures of LIN@CB[n] were optimized by DFTB+ in Materials Studio 2017. The resulting structures were used in DFT (B3LYP-gCP-D3/6-31G*) calculation by ORCA (version 4.2), when solvent effect was treated by CPCM.
DFTB+ calculation showed that LIN@CB[n=7] is more stable than other LIN@CB[n=5,6,8]. By using DFT, it was found out that i-CB[7] (mono-inverted CB[7]) can form relatively stable inclusion compound with LIN. The electronic spectra of LIN, i-CB[7] and LIN@i-CB[7] by ZINDO/S showed that λmax (262nm) of LIN@i-CB[7] was similar to that (263nm) of i-CB[7], which means that light absorption in LIN@i-CB[7] seems to be localized in i-CB[7], not in LIN. Therefore i-CB[7] can protect LIN from sunlight photolysis in LIN@i-CB[7].
The result has been published in "Structural Chemistry" under the title of "Quantum chemical study on inclusion of linalool into cucurbiturils"(https://doi.org/10.1007/s11224-023-02191-3).
