Testing the sensitivity limits of 33S NMR: An ultra-wideline study of elemental sulfur

Field-swept 33S NMR study of elemental sulfur

“…It has been found [7] that the differences between the C Q values for the four sulfur sites, calculated from DFT calculations, are small, less than 0.2 MHz. The results of our present study are reasonably in agreement with those of the previous studies [7,8]. It can be seen from Figure S1 in the Supporting Information that the four peaks moved to slightly higher frequencies as the temperature decreased.…”

“…Dehmelt [8] observed the four ␣-S 8 NQR signals at room temperature and found that the average C Q value was 45.8 MHz. O'Dell et al [7] found an average C Q value for ␣-S 8 of 43.3(2) MHz from the experimental NMR investigations and an average value of 40.4 MHz from density functional theory (DFT) calculations. It has been found [7] that the differences between the C Q values for the four sulfur sites, calculated from DFT calculations, are small, less than 0.2 MHz.…”

“…O'Dell et al [7] found an average C Q value for ␣-S 8 of 43.3(2) MHz from the experimental NMR investigations and an average value of 40.4 MHz from density functional theory (DFT) calculations. It has been found [7] that the differences between the C Q values for the four sulfur sites, calculated from DFT calculations, are small, less than 0.2 MHz. The results of our present study are reasonably in agreement with those of the previous studies [7,8].…”

“…The optimal temperature for ␣-S 8 was found to be 260 K, at which the QCPMG pulse sequence could be used successfully and the T 1 value was relatively short (approximately 5 ms). O'Dell et al [7] suggested that it would not realistically be possible to obtain 33 S NMR spectra of organic and biological molecules because of the experimental conditions (such as experimental time and signal intensities) that would be required for frequency-swept NMR measurements of elemental sulfur to be made at room temperature. However, we emphasize that there were no obstacles for obtaining 33 S NMR spectra of organic and biological systems using the approach presented here, which includes the measurement temperature into consideration.…”

“…Important breakthroughs in the 33 S NMR spectroscopy of compounds that form covalent bonds have been made in the past several years. O'Dell et al [7] demonstrated the usefulness of ultra-wideline techniques for measuring the frequency-swept 33 S NMR spectrum of ␣-S 8 at a magnetic field of 21.1 T. This gave the largest C Q value for 33 S that has yet been measured using NMR spectroscopy. The primary advantage of frequency-swept NMR spectroscopy is that the observational range can be extended as far as the spectrometer hardware allows.…”