title: Temperature-dependent 11B spin-lattice relaxation time for BF4 and CF3BF3 anions in room-temperature ionic liquids.
abstract: Temperature-dependent (11)B T(1) values were measured for the BF(4) anion and BF(3) in the CF(3)BF(3) anion in room-temperature ionic liquids (RTILs) composed of the cation N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium (DEME). Including the lithium-salt-doped samples, two neat and two binary ionic liquids were studied. Arrhenius plots of the (11)B T(1) showed T(1) minima for BF(4) in the temperature range between 243 (or above freezing) and 373 K. Using the Bloembergen, Pound, and Purcell(BPP) equations for the (11)B quadrupolar and (11)B-(19) F dipolar relaxation mechanisms, the correlation times for motions of BF(4) were calculated. Since the internal rotation of BF(3) is assumed in CF(3)BF(3), T(1) minimum was not observed. The effects of the addition of the lithium salt on the (11)B correlation time and (11)BT(1) for the anions in the ILs are discussed.
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Center, Tsukuba, Ibaraki 305-8565, Japan. hayamizu.k@aist.go.jp
authors.forename: Kikuko
authors.initials: K
authors.lastname: Hayamizu
authors.forename: Seiji
authors.initials: S
authors.lastname: Tsuzuki
authors.forename: Shiro
authors.initials: S
authors.lastname: Seki
mesh_terms: D000838:Anions / Q000737:chemistry; D001880:Boranes / Q000737:chemistry*; D001895:Boron / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D007554:Isotopes / Q000737:chemistry; D013696:Temperature
chemical_list: D000838:Anions; D001880:Boranes; D052578:Ionic Liquids; D007554:Isotopes; D001895:Boron