Molecular motion in solid ammonia trimethylalane
| Autor: | Gianina Tutoveanu, Kenneth D. M. Harris, Simon J. Kitchin, Jens Müller |
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| Rok vydání: | 2003 |
| Předmět: |
Chemistry
Relaxation (NMR) Spin–lattice relaxation Nuclear magnetic resonance spectroscopy Activation energy Condensed Matter Physics Resonance (chemistry) Electronic Optical and Magnetic Materials Inorganic Chemistry Dipole Nuclear magnetic resonance Chemical physics Materials Chemistry Ceramics and Composites Molecule Physical and Theoretical Chemistry Anisotropy |
| Zdroj: | Journal of Solid State Chemistry. 176:120-126 |
| ISSN: | 0022-4596 |
| DOI: | 10.1016/s0022-4596(03)00355-4 |
| Popis: | Solid state 2H NMR has been used to study molecular motion in deuterated ammonia trimethylalane (CH3)3AlND3. From analysis of the 2H NMR lineshape between 123 and 298 K, reorientation of the –ND3 group about the molecular Al–N axis is shown to occur at a rate higher than 108 s–1, and simulation of partially relaxed 2H NMR lineshapes shows that the reorientation can be described as a 3-site 120° jump motion. From the temperature dependence of the 2H spin–lattice relaxation time, the activation energy for this motion is estimated to be 9.3±0.3 kJ mol–1. There is no evidence from either 2H or 27Al NMR data for any site-exchange between the sites occupied by the –ND3 and –CH3 groups. The anisotropy of the dynamics of (CH3)3AlND3 indicates that the orientation of the Al–N bond is highly constrained, presumably by a strong interaction between the electric dipoles of neighboring molecules. |
| Databáze: | OpenAIRE |
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