Abstract
The 1H NMR spectrum of glycine in stretched gelatin gel and in cromolyn liquid crystal displays a well-resolved doublet due to 1H– 1H dipolar interaction. Multiple spectra were obtained within a wide range of offset frequencies of partially saturating radio-frequency (RF) radiation to generate steady-state irradiation envelopes or z-spectra of glycine. Maximal suppression of the doublet occurred when the irradiation was applied exactly at the centre frequency, between the two glycine peaks. This phenomenon is due to double-quantum transitions and is similar to our previous work on quadrupolar nuclei 2H (HDO) and 23Na +. When the 13C isotopomer glycine-2- 13C was used, the same effect was found in twice, split by 1 J CH + 2 D CH. Additional signals in 1H and 13C NMR due to prochiral–chiral interactions were found when glycine-2- 13C was dissolved in chiral anisotropic gelatin and κ-carrageenan gels. The NMR spectra were successfully simulated assuming a 2 J HH coupling constant of −16.5 Hz and two distinct dipolar coupling constants for the – 13CH 2– group ( D C,HA, and D C,HB).
Published Version
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