@article {440,
	title = {Orientation and Motion of Tetrahydrofuran in Graphite-Intercalation Compounds - Proton Nmr-Studies of Cs(Thf)(1.3)C-24 and K(Thf)(2.5)C-24},
	journal = {Journal of Physical Chemistry},
	volume = {99},
	year = {1995},
	note = {J Phys Chem-UsRg562Times Cited:5Cited References Count:31},
	month = {Jun 29},
	pages = {10565-10572},
	abstract = {<p>The orientation and motion of tetrahydrofuran (THF) in the ternary graphite intercalation compounds Cs-(THF)(1.3)C-24 and K(THF)(2.5)C-24 have been studied by proton NMR. Simulations of the NMR spectra indicate that the THF molecules in CS(THF)(1.3)C-24 have their mean planes oriented parallel to the layers of the host lattice, while the THF molecules in K(THF)(2.5)C-24 have their mean planes oriented at an angle between 50 degrees and 75 degrees from the graphite layers. The proton NMR spectra of both compounds show evidence that the THF molecules rotate about the normal to the graphite layers and confirm X-ray diffraction studies showing a degree of orientational disorder in the samples, corresponding to a mosaic spread in the graphite layer orientation. The conformation of the intercalated THF was studied by simulating the experimental NMR spectra using models for the conformational motion of THF. Simulations indicate that the conformation of intercalated THF is different than gas or liquid phase THF, which has been found to have a ring puckering amplitude of 0.38-0.44 Angstrom and to undergo nearly free pseudorotation through a series of conformations. Best agreement between simulated and experimental NMR spectra of Cs(THF)(1.3)C-24 was Obtained with THF interconverting between two conformations of C-s symmetry and a puckering amplitude of 0.30 Angstrom. Free or slightly hindered pseudorotation of THF (observed in liquid or gaseous THF) in this compound produces simulated spectra that differ significantly from the experimental spectra. Simulated proton NMR spectra of K(THF)(2.5)C-24 using conformations of C-s symmetry or free or slightly hindered pseudorotation of THF do not fit the experimental spectra sufficiently well to allow distinction between the conformational motions or to exclude other possible motions.</p>
},
	keywords = {system},
	isbn = {0022-3654},
	doi = {Doi 10.1021/J100026a020},
	url = {<Go to ISI>://WOS:A1995RG56200020},
	author = {Schmidt, C. and Rosen, M. E. and Caplan, D. F. and Pines, A. and Quinton, M. F.}
}
@article {473,
	title = {2-Dimensional Proton Nmr-Studies of the Conformations and Orientations of N-Alkanes in a Liquid-Crystal Solvent},
	journal = {Journal of Physical Chemistry},
	volume = {97},
	year = {1993},
	note = {J Phys Chem-UsKx596Times Cited:37Cited References Count:20},
	month = {Apr 15},
	pages = {3858-3866},
	abstract = {<p>Magnetic dipole couplings between pairs of protons in a series of n-alkanes (hexane through decane) dissolved in a nematic liquid crystal were measured by two-dimensional NMR spectroscopy. The dependence of dipole couplings on the distance between pairs of protons and on the orientation of the molecule with respect to the applied magnetic field make them a potentially rich source of information about molecular conformation and orientation. Interpretation of the dipole couplings, however, is complicated by the fact that the measured couplings are averaged over all molecular conformations and orientations sampled by the molecule. Thus, the couplings do not directly provide internuclear distances and orientations, but instead provide constraints on the time-averaged conformations and orientations of the n-alkane molecules that can be used as a rigorous test of models for intermolecular interactions in liquid crystals. Three models for solute-liquid crystal interactions were examined; the model proposed by Photinos et al.1 was found to be superior to the others in describing this system. The results of the modeling, including order parameters and conformer probabilities for the alkanes, are discussed and compared to n-alkanes in the liquid state.</p>
},
	keywords = {size},
	isbn = {0022-3654},
	doi = {Doi 10.1021/J100117a037},
	url = {<Go to ISI>://WOS:A1993KX59600037},
	author = {Rosen, M. E. and Rucker, S. P. and Schmidt, C. and Pines, A.}
}
@article {522,
	title = {2-Dimensional Nmr-Studies of Flexible Molecules in Liquid-Crystals - Orientational Order and Conformational Probabilities of N-Hexane},
	journal = {Molecular Physics},
	volume = {69},
	year = {1990},
	note = {Mol PhysCy544Times Cited:38Cited References Count:55},
	month = {Mar},
	pages = {671-695},
	isbn = {0026-8976},
	doi = {Doi 10.1080/00268979000100501},
	url = {<Go to ISI>://WOS:A1990CY54400007},
	author = {Gochin, M. and Pines, A. and Rosen, M. E. and Rucker, S. P. and Schmidt, C.}
}
