Unusual complex formation and chemical reaction of haloacetate anion on the exterior surface of cucurbit[6]uril in the gas phase

Tae Su Choi, Jae Yoon Ko, Sung Woo Heo, Young Ho Ko, Kimoon Kim, Hugh I. Kim

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12 Citations (Scopus)


Noncovalent interactions of cucurbit[6]uril (CB[6]) with haloacetate and halide anions are investigated in the gas phase using electrospray ionization ion mobility mass spectrometry. Strong noncovalent interactions of monoiodoacetate, monobromoacetate, monochloroacetate, dichloroacetate, and trichloroacetate on the exterior surface of CB[6] are observed in the negative mode electrospray ionization mass spectra. The strong binding energy of the complex allows intramolecular SN2 reaction of haloacetate, which yields externally bound CB[6]-halide complex, by collisional activation. Utilizing ion mobility technique, structures of exteriorly bound CB[6] complexes of haloacetate and halide anions are confirmed. Theoretically determined low energy structures using density functional theory (DFT) further support results from ion mobility studies. The DFT calculation reveals that the binding energy and conformation of haloacetate on the CB[6] surface affect the efficiency of the intramolecular SN2 reaction of haloacetate, which correlate well with the experimental observation.

Original languageEnglish
Pages (from-to)1786-1793
Number of pages8
JournalJournal of the American Society for Mass Spectrometry
Issue number10
Publication statusPublished - 2012 Oct 1



  • Anionic complex
  • CB[6]
  • Cucurbit[6]uril
  • Electrospray ionization
  • Halide
  • Haloacetate
  • Intramolecular S2 reaction
  • Ion mobility spectrometry

ASJC Scopus subject areas

  • Structural Biology
  • Spectroscopy

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