Characterization of inclusion complexation of various tetraalkylammonium chlorides with cucurbit[7]uril by external high-pressure studies

Yuki Matsumoto, Naoya Inazumi, Tadashi Hanaya, Yoshimi Sueishi

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1 Citation (Scopus)

Abstract

The inclusion constants of tetraalkylammonium salts (ASs) with cucurbit[7]uril (CB[7]) were determined at high-pressures using methylene blue as a chemical indicator. CB[7] formed 1:1 inclusion complexes with ASs. We found a characteristic dependence of the alkyl chain substituents in ASs on the inclusion equilibrium, which was responsible for the formation of clathrate hydrates of the AS in bulk. Furthermore, we examined the effects of external high pressures on the CB[7] inclusion complexations of ASs having different alkyl chain lengths. Pressure dependence experiments allowed us to calculate the reaction volume (ΔV) upon inclusion; i.e., the volume change (ΔVdesolv) accompanying desolvation around the guest molecules and the volume change (ΔVrepel) caused by the water molecules repelled from the CB[7] cavity. The volumetric study for the inclusion of ASs with CB[7] showed that in the tetraheptylammonium ion, one arm (alkyl chain) was encapsulated in the CB[7] cavity, while in other ASs, two arms were located in the cavity. NMR measurements of the complexes and pressure-dependent studies provided unique information on the structures of the inclusion complexes of ASs with CB[7].

Original languageEnglish
Pages (from-to)205-210
Number of pages6
JournalJournal of Inclusion Phenomena and Macrocyclic Chemistry
Volume92
Issue number1-2
DOIs
Publication statusPublished - Oct 1 2018

Fingerprint

Cucurbitaceae
Complexation
Chlorides
chlorides
inclusions
Pressure
cavities
chemical indicators
Molecules
methylene blue
Methylene Blue
clathrates
cucurbit(7)uril
Hydrates
Chain length
hydrates
pressure dependence
molecules
Salts
Nuclear magnetic resonance

Keywords

  • Cucurbit[7]uril
  • Inclusion complexation
  • Pressure effect
  • Tetraalkylammonium salt
  • Volumetric study

ASJC Scopus subject areas

  • Food Science
  • Chemistry(all)
  • Condensed Matter Physics

Cite this

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title = "Characterization of inclusion complexation of various tetraalkylammonium chlorides with cucurbit[7]uril by external high-pressure studies",
abstract = "The inclusion constants of tetraalkylammonium salts (ASs) with cucurbit[7]uril (CB[7]) were determined at high-pressures using methylene blue as a chemical indicator. CB[7] formed 1:1 inclusion complexes with ASs. We found a characteristic dependence of the alkyl chain substituents in ASs on the inclusion equilibrium, which was responsible for the formation of clathrate hydrates of the AS in bulk. Furthermore, we examined the effects of external high pressures on the CB[7] inclusion complexations of ASs having different alkyl chain lengths. Pressure dependence experiments allowed us to calculate the reaction volume (ΔV) upon inclusion; i.e., the volume change (ΔVdesolv) accompanying desolvation around the guest molecules and the volume change (ΔVrepel) caused by the water molecules repelled from the CB[7] cavity. The volumetric study for the inclusion of ASs with CB[7] showed that in the tetraheptylammonium ion, one arm (alkyl chain) was encapsulated in the CB[7] cavity, while in other ASs, two arms were located in the cavity. NMR measurements of the complexes and pressure-dependent studies provided unique information on the structures of the inclusion complexes of ASs with CB[7].",
keywords = "Cucurbit[7]uril, Inclusion complexation, Pressure effect, Tetraalkylammonium salt, Volumetric study",
author = "Yuki Matsumoto and Naoya Inazumi and Tadashi Hanaya and Yoshimi Sueishi",
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T1 - Characterization of inclusion complexation of various tetraalkylammonium chlorides with cucurbit[7]uril by external high-pressure studies

AU - Matsumoto, Yuki

AU - Inazumi, Naoya

AU - Hanaya, Tadashi

AU - Sueishi, Yoshimi

PY - 2018/10/1

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N2 - The inclusion constants of tetraalkylammonium salts (ASs) with cucurbit[7]uril (CB[7]) were determined at high-pressures using methylene blue as a chemical indicator. CB[7] formed 1:1 inclusion complexes with ASs. We found a characteristic dependence of the alkyl chain substituents in ASs on the inclusion equilibrium, which was responsible for the formation of clathrate hydrates of the AS in bulk. Furthermore, we examined the effects of external high pressures on the CB[7] inclusion complexations of ASs having different alkyl chain lengths. Pressure dependence experiments allowed us to calculate the reaction volume (ΔV) upon inclusion; i.e., the volume change (ΔVdesolv) accompanying desolvation around the guest molecules and the volume change (ΔVrepel) caused by the water molecules repelled from the CB[7] cavity. The volumetric study for the inclusion of ASs with CB[7] showed that in the tetraheptylammonium ion, one arm (alkyl chain) was encapsulated in the CB[7] cavity, while in other ASs, two arms were located in the cavity. NMR measurements of the complexes and pressure-dependent studies provided unique information on the structures of the inclusion complexes of ASs with CB[7].

AB - The inclusion constants of tetraalkylammonium salts (ASs) with cucurbit[7]uril (CB[7]) were determined at high-pressures using methylene blue as a chemical indicator. CB[7] formed 1:1 inclusion complexes with ASs. We found a characteristic dependence of the alkyl chain substituents in ASs on the inclusion equilibrium, which was responsible for the formation of clathrate hydrates of the AS in bulk. Furthermore, we examined the effects of external high pressures on the CB[7] inclusion complexations of ASs having different alkyl chain lengths. Pressure dependence experiments allowed us to calculate the reaction volume (ΔV) upon inclusion; i.e., the volume change (ΔVdesolv) accompanying desolvation around the guest molecules and the volume change (ΔVrepel) caused by the water molecules repelled from the CB[7] cavity. The volumetric study for the inclusion of ASs with CB[7] showed that in the tetraheptylammonium ion, one arm (alkyl chain) was encapsulated in the CB[7] cavity, while in other ASs, two arms were located in the cavity. NMR measurements of the complexes and pressure-dependent studies provided unique information on the structures of the inclusion complexes of ASs with CB[7].

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