title: High-resolution characterization of liquid-crystalline [60]fullerenes using solid-state nuclear magnetic resonance spectroscopy.
abstract: Liquid-crystalline materials containing fullerenes are valuable in the development of supramolecular switches and in solar cell technology. In this study, we characterize the liquid-crystalline and dynamic properties of fullerene-containing thermotropic compounds using solid-state natural abundance (13)C NMR experiments under stationary and magic angle spinning sample conditions. Chemical shifts spectra were measured in isotropic, liquid-crystalline nematic and smectic A and crystalline phases using one-dimensional (13)C experiments, while two-dimensional separated local-field experiments were used to measure the (1)H- (13)C dipolar couplings in mesophases. Chemical shift and dipolar coupling parameters were used to characterize the structure and dynamics of the liquid-crystalline dyads. NMR data of fullerene-containing thermotropic liquid crystals are compared to that of basic mesogenic unit and mesomorphic promoter compounds. Our NMR results suggest that the fullerene-ferrocene dyads form highly dynamic liquid-crystalline phases in which molecules rotate fast around the symmetry axis on the characteristic NMR time scale of approximately 10 (-4) s.
authors.affiliation: Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Dvinskikh
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Yamamoto
authors.forename: David
authors.initials: D
authors.lastname: Scanu
authors.forename: Robert
authors.initials: R
authors.lastname: Deschenaux
authors.forename: Ayyalusamy
authors.initials: A
authors.lastname: Ramamoorthy
mesh_terms: D037741:Fullerenes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy
chemical_list: D037741:Fullerenes; C069837:fullerene C60