ZfN: Search Results

1	Author	Takashige Shimizu, Tetsuo Asaji, Daiyu Nakamura, Ryuichi Ikeda	Requires 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
	Similar Items	Find
	DEBUG INFO
	TEI-XML for	default:Reihe_A/47/ZNA-1992-47a-0283.pdf
	Identifier	ZNA-1992-47a-0283
	Volume	47

2	Author	Yoshio Kume, Maki Tokoro, Tetsuo Asaji, Ryuichi Ikeda, Daiyu Nakamura	Requires 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
	Similar Items	Find
	DEBUG INFO
	TEI-XML for	default:Reihe_A/47/ZNA-1992-47a-0288.pdf
	Identifier	ZNA-1992-47a-0288
	Volume	47

3	Author	Takeshi Kyan, Hamagawa, Takahiro Isono, Masao Hashimoto	Requires 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
	Similar Items	Find
	DEBUG INFO
	TEI-XML for	default:Reihe_A/47/ZNA-1992-47a-0299.pdf
	Identifier	ZNA-1992-47a-0299
	Volume	47

4	Author	Masao Hashimoto, Takahiro Isono, Noriko Yomesaka, Haruo Niki, Hiroshi Kyan, Takeshi Hamagawa	Requires 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
	Similar Items	Find
	DEBUG INFO
	TEI-XML for	default:Reihe_A/47/ZNA-1992-47a-0293.pdf
	Identifier	ZNA-1992-47a-0293
	Volume	47