| | 1 | Author
| Makoto Kaga, Piotr Koziol, Tetsuo Asaji, Daiyu Nakamura | Requires cookie* | | | Title
| Electric field Gradient Modulation by Motion of Lone-Pair Electrons in [(CH 3 ) 3 S] 2 MC1 6 (M = Pt, Sn) as a Possible Relaxation Mechanism of Chlorine Nuclear Quadrupole Resonance  | | | | Abstract
| The temperature dependence of the chlorine NQR spin-lattice relaxation time T^was observed for trimethylsulfonium hexachlorometallates(IV), [(CH 3) 3 S] 2 MC1 6 (M = Pt, Sn), trimethylammonium hexachlorostannate(IV), [(CH 3) 3 NH] 2 SnCl 6 , and tetramethylphosphonium hexachlorostannate(IV), [(CH 3) 4 P] 2 SnCl 6 . The quadrupolar relaxation in [(CH 3) 3 NH] 2 SnCl 6 and [(CH 3) 4 P] 2 SnCl 6 can be described by the usual librational and reorientational motion of the complex anion at lower and higher temperatures, respectively. Besides T 1Q due to these two mechanisms, T 1Q minimum was observed at ca. 90 and 120 K for [(CH 3) 3 S] 2 PtCl 6 and [(CH 3) 3 S] 2 SnCl 6 , respectively, which is attributable to the electric field gradient modulation by the motion of the [(CH 3) 3 S] + cation having lone-pair electrons. The activation energies for the isotropic reorientation of the complex anion were determined as46,65, 59, and 60 kJ mol^ for [(CH 3) 4 P] 2 SnCl 6 , [(CH 3) 3 NH] 2 SnCl 6 , [(CH 3) 3 S] 2 PtCl 6 , and [(CH 3) 3 S] 2 SnCl 6 , respectively. | | | |
Reference
| Z. Naturforsch. 45a, 1033—1037 (1990); received May 26 1990 | | | |
Published
| 1990 | | | |
Keywords
| Nuclear Quadrupole Resonance, Spin-Lattice Relaxation, EFG Modulation, Lone-Pair Electrons | | | |
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| default:Reihe_A/45/ZNA-1990-45a-1033.pdf | | | | Identifier
| ZNA-1990-45a-1033 | | | | Volume
| 45 | |
| 2 | Author
| Makoto Kaga, Tetsuo Asaji, Ryuichi Ikeda, Daiyu Nakamura | Requires cookie* | | | Title
| Chlorine Nuclear Quadrupole Relaxation and Cationic Motion in Trimethylsulfonium Hexachloroselenate(IV): [(CH 3 ) 3 Sl 2 SeCl^ | | | | Abstract
| The 35 C1 NQR spin-lattice and spin-spin relaxation times, 7^ and T2Q, respectively, and the 'H NMR spin-lattice relaxation time T1H at 32 and 60 MHz were determined for [(CH3j3S]2SeCl6 as functions of temperature. The rapid decrease of observed above ca. 250 K with increasing temperature was attributed to the onset of reorientation of the [SeCl6] 2 " complex anion with the activation energy £a = 42 + 5 kJ mol -1 . When cooled from ca. 250 K, T1Q showed an anomalous decrease. This 7"1Q decrease was explained by electric field gradient modulation related to some cationic motion. Possible origins of the cationic motion are discussed. | | | |
Reference
| Z. Naturforsch. 47a, 274—276 (1992); received July 19 1991 | | | |
Published
| 1992 | | | |
Keywords
| Spin-lattice relaxation, NQR, NMR, EFG modulation, Molecular motion | | | |
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| default:Reihe_A/47/ZNA-1992-47a-0274.pdf | | | | Identifier
| ZNA-1992-47a-0274 | | | | Volume
| 47 | |
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