Studying Supramolecular Assemblies by ESEEM Spectroscopy: Inclusion Complexes of Cyclodextrins

Gabriela Ionita, Marc Florent, Daniella Goldfarb, Victor Chechik

Research output: Contribution to journalArticlepeer-review

Abstract

Electron spin-echo envelope modulation (ESEEM) spectroscopy was used to investigate intramolecular and intermolecular complexes of cyclodextrins (CDs) with a nitroxide group. The interaction with solvent molecules (D2O) was followed through the H-2 modulation depth. Competition experiments with adamantane-type guests were used to confirm complexation. The shielding of the nitroxide group from solvent upon inclusion into a CD cavity made this technique more sensitive to complexation than cw EPR spectroscopy. ESEEM analysis of a series of CDs mono and bis spin-labeled on the primary rim of the cavity showed that only one compound formed a self-inclusion complex. This suggests that significant linker length/flexibility is required for formation of inclusion complexes in functionalized CDs. DEER (double electron-electron resonance) experiments confirmed that the self-inclusion complex of the spin-labeled CD was intra- rather than intermolecular.

Original languageEnglish
Pages (from-to)5781-5787
Number of pages7
JournalJournal of Physical Chemistry B
Volume113
Issue number17
DOIs
Publication statusPublished - 30 Apr 2009

Keywords

  • ELECTRON-SPIN-RESONANCE
  • MESOPOROUS MATERIAL SBA-15
  • BETA-CYCLODEXTRIN
  • LABELED CYCLODEXTRINS
  • NITROXIDE RADICALS
  • CIRCULAR-DICHROISM
  • BIMODAL INCLUSION
  • GENERAL RULE
  • EPR
  • MODULATION

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