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Preferential binding of unsaturated hydrocarbons in aryl-bisimidazolium·cucurbit[8]uril complexes furbishes evidence for small-molecule ?-? interactions.

ABSTRACT: Whilst cucurbit[n]urils (CBn) have been utilized in gas encapsulation, only the smaller CBn (n = 5 and 6) have utility given their small cavity size. In this work, we demonstrate that the large cavity of CB8 can be tailored for gaseous and volatile hydrocarbon encapsulation by restricting its internal cavity size with auxiliary aryl-bisimidazolium (Bis, aryl = phenyl, naphthyl, and biphenyl) guests. The binding constants for light hydrocarbons (C ? 4) are similar to those measured with CB6, while larger values are obtained with Bis·CB8 for larger guests. A clear propensity for higher affinities of alkenes relative to alkanes is observed, most pronounced with the largest delocalized naphthalene residue in the auxiliary Bis guest, which provides unique evidence for sizable small-molecule ?-? interactions.

SUBMITTER: Barrow SJ

PROVIDER: S-EPMC7006508 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

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Preferential binding of unsaturated hydrocarbons in aryl-bisimidazolium·cucurbit[8]uril complexes furbishes evidence for small-molecule π-π interactions.

Barrow Steven J SJ Assaf Khaleel I KI Palma Aniello A Nau Werner M WM Scherman Oren A OA

Chemical science 20191017 44

Whilst cucurbit[n]urils (CBn) have been utilized in gas encapsulation, only the smaller CBn (n = 5 and 6) have utility given their small cavity size. In this work, we demonstrate that the large cavity of CB8 can be tailored for gaseous and volatile hydrocarbon encapsulation by restricting its internal cavity size with auxiliary aryl-bisimidazolium (Bis, aryl = phenyl, naphthyl, and biphenyl) guests. The binding constants for light hydrocarbons (C ≤ 4) are similar to t ...[more]

PMID: 32110310

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