title: Solid-state NMR and computational studies of tetratolyl urea calix[4]arene inclusion compounds.
abstract: Solid-state guest dynamics of tetratolyl tetraurea calix[4]arene tetrapentylether dimeric capsules filled with different types of aromatic guests such as benzene-d6, fluorobenzene-d5 and 1,4-difluorobenzene were studied. Upon inclusion, all guest moieties revealed complexation-induced shifts varying from 2.8 ppm to 5.1 ppm. All guest molecules were shown to undergo distinct motions, ranging from mere C6-rotations of benzene-d6 to (ill-defined) 180 degrees phenyl flips of fluorobenzene-d5. In all cases, dynamic heterogeneities were identified based on 2H lineshape deconvolution. In addition, by combination of both a computed nucleus independent chemical shift (NICS) map and explicit 19F and 2H ab initio DFT chemical shift calculations, the preferred orientation of the guest molecules within the host was derived.
authors.affiliation: Max-Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany.
authors.forename: Chulsoon
authors.initials: C
authors.lastname: Moon
authors.forename: Gunther
authors.initials: G
authors.lastname: Brunklaus
authors.forename: Daniel
authors.initials: D
authors.lastname: Sebastiani
authors.forename: Yuliya
authors.initials: Y
authors.lastname: Rudzevich
authors.forename: Volker
authors.initials: V
authors.lastname: Böhmer
authors.forename: Hans Wolfgang
authors.initials: HW
authors.lastname: Spiess
mesh_terms: D001554:Benzene / Q000737:chemistry; D047250:Calixarenes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D010636:Phenols / Q000737:chemistry*; D011789:Quantum Theory; D014508:Urea / Q000737:chemistry*
chemical_list: D010636:Phenols; C121325:calix(4)arene; D047250:Calixarenes; D014508:Urea; D001554:Benzene