Abstract:
NMR second moments M2 and spin-lattice relaxation times in the laboratory and rotating frame T1 and T1ρ for trimethyloxosulphonium fluoride, chloride, bromide and iodide are reported over a wide temperature range. The variations of M2, T1 and T1ρ for each of these salts are interpreted in terms of methyl group reorientation about its C3 axis and reorientation of the TMOS ion about its C3' symmetry axis; the respective activation parameters are estimated. It is found that trimethyloxosulphonium chloride contains two types of methyl groups statistically weighted in the ratio 2:1, reorienting with different frequencies about their C3 axes.
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