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'Hydrogen Bonds' in keywords Facet   section ZfN Section A  [X]
Facet   Publication Year 1992  [X]
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1992[X]
1Author    Takashige Shimizu, Tetsuo Asaji, Daiyu Nakamura, Ryuichi IkedaRequires cookie*
 Title    Uniaxial Reorientation of Octahedral Complex Anions Excited in Triethylammonium Hexachlorostannate (IV) Crystals  
 Abstract    The temperature dependence of the 35 C1 NQR spin-latticew relaxation time T1Q has been deter-mined for the three resonance lines observed in [(C2H5)3NH]2SnCl6. The higher frequency lines fade out around 150 K upon heating, whereas the lowest line shows up to room temperature no anomaly, although these three lines are assigned to chlorines belonging to the same complex anion. The T1Q values of the higher two lines decrease exponentially around the fade-out temperature, where T iq of the lowest line shows no such behavior. These results are explained by the onset of uniaxial reorientations of the octahedral complex ions by 90° about the Cl-Sn-Cl axis containing the lowest frequency chlorines. The activation energy (£J of this reorientation (22-24 kJ moP 1) is the lowest so far reportd for [SnCl6] 2-ions. £a about the other axes is 67 kJ mop 1 , indicating a remarkable anisotropic reorientation. 
  Reference    Z. Naturforsch. 47a, 283—287 (1992); received July 19 1991 
  Published    1992 
  Keywords    Spin-Lattice Relaxation, NQR, NMR, Reorientational Motion, Hydrogen Bond 
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 TEI-XML for    default:Reihe_A/47/ZNA-1992-47a-0283.pdf 
 Identifier    ZNA-1992-47a-0283 
 Volume    47 
2Author    Yoshio Kume, Maki Tokoro, Tetsuo Asaji, Ryuichi Ikeda, Daiyu NakamuraRequires cookie*
 Title    Reorientational Motion of Hydrogen Bonded Octahedral Complex Anions in Hydrazinium Hexachlorostannate(IV), (N 2 H 5 ) 2 SnCl 6 , as Studied by 35 C1 NQR Spin-Lattice Relaxation Measurements  
 Abstract    The temperature dependences of NQR frequencies and spin-lattice relaxation times, T1Q, of 35 C1 in (N2H5)2SnCl6 were measured. Four NQR signals distributed in a fairly wide frequency range were observed, the lowest-frequency line exhibiting an anomalous positive temperature coefficient. The highest-frequency line showed a steep temperature dependence. These results could be interpreted by considering the intermolecular interaction between CI and -NH2 in N2H^. Below ca. 250 K, T1Q of the upper three signals exhibited a gradual decrease upon heating, explainable by lattice vibra-tions, while a shallow Tig minimum, ascribable to the modulation of electric quadrupole interaction, was observed at ca. 11ÖK for the lowest-frequency signal. The reorientation of [SnCl6] 2 ~ was elucidated to be highly anisotropic, in that it reorients about one of the CI-Sn-Cl axes much more frequently than about the other two axes. The activation energies were determined to be 62 and 94 kj mol -1 for the respective reorientations. 
  Reference    Z. Naturforsch. 47a, 288—292 (1992); received July 17 1991 
  Published    1992 
  Keywords    Key word: Spin-Lattice Relaxation, NQR, NMR, Reorientational Motion, Hydrogen Bond 
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 TEI-XML for    default:Reihe_A/47/ZNA-1992-47a-0288.pdf 
 Identifier    ZNA-1992-47a-0288 
 Volume    47 
3Author    Takeshi Kyan, Hamagawa, Takahiro Isono, Masao HashimotoRequires cookie*
 Title    Hiroshi  
 Abstract    The crystal structure of cyclohexylhemiacetal (cycHx-CH) was determined at 296 K: monoclinic, space group P2 Jc, a =1028.7 (9), b = 609.5 (1), c = 1811.9 (4) pm, and ß = 99.79 (3)°, Z -4, R = 0.0552. The three 5s Cl NQR lines in cycHx-CH, T., T2, and T2*, were measured by a pulsed method at 80-300 K. Below 200 K Tf 1 obeyed the T law well, indicating that the spin lattice relaxation is governed by lattice vibrations. The reorientation of CC13 seems to be responsible for the sharp T: drop observed above 250 K. Shoulders in the T { vs. 1/T curves indicate the presence of Ti minima at about 240 K. A fluctuation of the EFG due to a dynamic disorder of hydrogen atoms in the OH groups is assumed to explain the T x minima. 
  Reference    Z. Naturforsch. 47a, 299 (1992); received July 25 1991 
  Published    1992 
  Keywords    Chlorine NQR, Spin-lattice relaxation, Hydrogen bond, Crystal structure 
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 TEI-XML for    default:Reihe_A/47/ZNA-1992-47a-0299.pdf 
 Identifier    ZNA-1992-47a-0299 
 Volume    47 
4Author    Masao Hashimoto, Takahiro Isono, Noriko Yomesaka, Haruo Niki, Hiroshi Kyan, Takeshi HamagawaRequires cookie*
 Title    Reorientation of the CC1 3 Group in Chloral 4-Chlorobenzyl- hemiacetal. A Pulsed 35 C1 NQR and X-ray Study  
 Abstract    The crystal structure of the title compound was determined at 291 K: monoclinic, space group C^h-P21/n, Z = 4, a = 1693.2(1), 6 = 579.3(1), c = 1232.5(1) pm, and ß = 107.21 (1)°, R = 0.0415. A sharp decrease of of Cl NQR found at T> 270 K for the CC13 group is attributed to the reorientation of the group over a potential barrier of ca. 50 kJ/mol. Intermolecular interactions between the CC13 and the neighboring atoms seem to dominate the magnitude of the potential barrier. T{~ 1 of the 35 C1 NQR of the Cl atom on the benzene ring obeyed the T 2 law well in the range 80 < T/K <270, while at T>280 K it deviated from the T 2 law. 
  Reference    Z. Naturforsch. 47a, 293—298 (1992); received July 25 1991 
  Published    1992 
  Keywords    Crystal structure, Hydrogen bond, Chlorine NQR, Spin lattice relaxation, Atom-atom potential method 
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 TEI-XML for    default:Reihe_A/47/ZNA-1992-47a-0293.pdf 
 Identifier    ZNA-1992-47a-0293 
 Volume    47