EPR Studies of the Binding Properties,Guest Dynamics,and Inner‐Space Dimensions of a Water‐Soluble Resorcinarene Capsule |
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| Authors: | Dr Mehmet Menaf Ayhan Dr Gilles Casano Dr Hakim Karoui Prof Antal Rockenbauer Dr Valérie Monnier Dr Micaël Hardy Prof Paul Tordo Dr David Bardelang Dr Olivier Ouari |
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| Affiliation: | 1. Aix‐Marseille Université, CNRS, Institut de Chimie Radicalaire, UMR 7273, 13013 Marseille (France);2. Department of Chemistry, Gebze Technical University, P.K.:141, 41400 Gebze, Kocaeli (Turkey);3. Institute of Materials and Environmental Chemistry, Hungarian Academy of Sciences and, Department of Physics, Budapest University of Technology and Economics, Budafoki ut 8, 1111 Budapest (Hungary);4. Aix‐Marseille Université, CNRS, Spectropole, FR 1739, 13013 Marseille (France) |
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| Abstract: | Nitroxide free radicals have been used to study the inner space of one of Rebek’s water‐soluble capsules. EPR and 1H NMR spectroscopy, ESI‐MS, and DFT calculations showed a preference for the formation of 1:2 complexes. EPR titrations allowed us to determine binding constants (Ka) in the order of 107 M ?2. EPR spectral‐shape analysis provided information on the guest rotational dynamics within the capsule. The interplay between optimum hydrogen bonding upon capsule formation and steric strain for guest accommodation highlights some degree of flexibility for guest inclusion, particularly at the center of the capsule where the hydrogen bond seam can be barely distorted or slightly disturbed. |
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| Keywords: | capsules EPR spectroscopy host– guest systems nitroxides supramolecular chemistry |
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