Coupled methyl groups in dimethyl sulphide
نویسنده
چکیده
Low field methyl tunnelling spectra of dimethyl sulphide have been measured using field cycling NMR and indicate the existence of two distinct methyl groups with tunnel. frequencies of 100kHz and 750kHz. Spectra show a significant broadening of the Larmor peak at those fields at which the Larmor and tunnel frequencies are equal. These are resonances between the rotational and spin dynamics of the methyl groups. An associated" change in the intensity and position of the 100kHz sidebands suggests that methyl group coupling may be responsible for these effects. Narrow 100kHz sidebands are restored by irradiating with an external RF field of this frequency which we suggest is due to decoupling of the rotor pairs. Measurements on partially deuterated dimethyl suphide show that the coupling cannot be intra-molecular.
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