1 Ocak 2019 Dergi makalesi Açık Erişim

Pavlovic, Radoslav Z.; Lei Zhiquan; Guney, Murat; Lalisse, Remy F.; Hopf, Ryan G.; Gallucci, Judith; Moore, Curtis; Xie, Han; Hadad, Christopher M.; Badjic, Jovica D.

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{
  "DOI": "10.1002/chem.201903006", 
  "abstract": "In this work, we report a mechanism by which stereoisomeric and twisted capsules P/M-1 direct their dynamic chirality in the presence of haloalkane guests. The capsule comprises a static, but twisted, cage that is linked to a dynamic tris(2-pyridylmethyl)amine (TPA) lid at its top. From the results of experimental (NMR spectroscopy and X-ray crystallography) and computational (DFT) studies, the TPA lid was shown to assume clockwise (+) and counterclockwise (-) folds with diastereomeric (but racemic) capsules M-1(+) and M-1(-) interconverting at a rapid rate (Delta G(189K)(not equal)=9.1 kcal mol(-1)). The relative stability of the capsules was found to be a function of guest(s) residing in their interior (243/262 angstrom(3)) with small CH2Cl2 (61 angstrom(3)) yielding roughly equal population of diastereomeric inclusion complexes. Larger guests, such as CCl4 (89 angstrom(3)) and CBr4 (108 angstrom(3)), however, formed M-1(-)subset of CX4 at the expense of M-1(+)subset of CX4 in circa 3:1 ratio. To account for the observation, theory (DFT:M06-2X/6-31+G*) and experiments (H-1 NMR spectroscopy) were used to deduce that CX4 guests become localized inside the twisted cage of the capsule by forming a C-X...pi halogen bond [N-c=d/(r(H)+r(X))=0.91-0.92] with the benzene \"floor\" while encountering electrostatic repulsions with closer naphthalimide boundaries. At last, the TPA lid used its central methylene hydrogens to establish, within the M-1(-)subset of CX4, three stabilizing C-H...X-C interactions with the guest. The same C-H...X-C interactions, however, became weaker (or possibly vanished) after the conformational reorganization of the lid and the formation of less stable M-1(+)subset of CX4 complex. On individual basis, C-H...X-C intermolecular contacts are weak and hardly detectable in the solution phase. In the case of capsule P/M-1, however, these contacts were multivalent and altogether strong enough to direct the host's dynamic chirality.", 
  "author": [
    {
      "family": "Pavlovic", 
      "given": " Radoslav Z."
    }, 
    {
      "family": "Lei Zhiquan"
    }, 
    {
      "family": "Guney", 
      "given": " Murat"
    }, 
    {
      "family": "Lalisse", 
      "given": " Remy F."
    }, 
    {
      "family": "Hopf", 
      "given": " Ryan G."
    }, 
    {
      "family": "Gallucci", 
      "given": " Judith"
    }, 
    {
      "family": "Moore", 
      "given": " Curtis"
    }, 
    {
      "family": "Xie", 
      "given": " Han"
    }, 
    {
      "family": "Hadad", 
      "given": " Christopher M."
    }, 
    {
      "family": "Badjic", 
      "given": " Jovica D."
    }
  ], 
  "container_title": "CHEMISTRY-A EUROPEAN JOURNAL", 
  "id": "72453", 
  "issue": "57", 
  "issued": {
    "date-parts": [
      [
        2019, 
        1, 
        1
      ]
    ]
  }, 
  "page": "13124-13130", 
  "title": "Multivalent C-H...Cl/Br-C Interactions Directing the Resolution of Dynamic and Twisted Capsules", 
  "type": "article-journal", 
  "volume": "25"
}