We report the analysis of the structure and dynamics of the calix[4]arene bis-crown derivative (Dc3) and the host-guest system formed by Dc3 and acetonitrile in a chloroform solution. NMR spectral measurements, molecular mechanics, and molecular dynamics calculations have been used. Results showed that the hostguest complex in solution has chemical shift values that are considerably different from those of the pure compounds and from the Dc3-acetonitrile mixture. Molecular mechanics simulations showed that Dc3 has a cavity with an almost circular cone shape and that the CN group of acetonitrile in the host-guest complex pointed toward the outside of the cavity. This orientation appeared energetically favored. The value of the generalized order parameter from C-NMR relaxation rates also showed that the methyl group of acetonitrile behaved as a free rotor in the Dc3 cavity with reorientational motion of almost two orders of magnitude faster than the aromatic carbons.
Bonechi, C., Donati, A., Martini, S., Rossi, C., Arduini, A., Pochini, A., et al. (2004). Analysis of the p-tert-Butylcalix[4]arene derivative (Dc3)-Acetonitrile host-guest complexing behaviour by Nuclear Magnetic Resonance (NMR) Spectroscopy and Computation Methods. JOURNAL OF PHYSICAL CHEMISTRY. B, CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES & BIOPHYSICAL, 108(23), 7603-7610 [10.1021/jp037464e].
Analysis of the p-tert-Butylcalix[4]arene derivative (Dc3)-Acetonitrile host-guest complexing behaviour by Nuclear Magnetic Resonance (NMR) Spectroscopy and Computation Methods
Bonechi C.;Donati A.;Rossi C.;
2004-01-01
Abstract
We report the analysis of the structure and dynamics of the calix[4]arene bis-crown derivative (Dc3) and the host-guest system formed by Dc3 and acetonitrile in a chloroform solution. NMR spectral measurements, molecular mechanics, and molecular dynamics calculations have been used. Results showed that the hostguest complex in solution has chemical shift values that are considerably different from those of the pure compounds and from the Dc3-acetonitrile mixture. Molecular mechanics simulations showed that Dc3 has a cavity with an almost circular cone shape and that the CN group of acetonitrile in the host-guest complex pointed toward the outside of the cavity. This orientation appeared energetically favored. The value of the generalized order parameter from C-NMR relaxation rates also showed that the methyl group of acetonitrile behaved as a free rotor in the Dc3 cavity with reorientational motion of almost two orders of magnitude faster than the aromatic carbons.
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https://hdl.handle.net/11365/19004
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