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13 C NMR Spectrum of DMSO-d 6. Pure deuterated DMSO shows no peaks in 1 H NMR spectroscopy and as a result is commonly used as an NMR solvent. [2] However commercially available samples are not 100% pure and a residual DMSO-d 5 1 H NMR signal is observed at 2.50ppm (quintet, J HD =1.9Hz). The 13 C chemical shift of DMSO-d 6 is 39.52ppm (septet ...
Deuterium NMR has a range of chemical shift similar to proton NMR but with poor resolution, due to the smaller magnitude of the magnetic dipole moment of the deuteron relative to the proton. It may be used to verify the effectiveness of deuteration: a deuterated compound will show a strong peak in 2 H NMR but not proton NMR.
To be NMR-active, a nucleus must have a non-zero nuclear spin (I ≠ 0). [8] It is this non-zero spin that enables nuclei to interact with external magnetic fields and show signals in NMR. Atoms with an odd sum of protons and neutrons exhibit half-integer values for the nuclear spin quantum number (I = 1/2, 3/2, 5/2, and so on). These atoms are ...
Deuterated solvents are a group of compounds where one or more hydrogen atoms are substituted by deuterium atoms. These isotopologues of common solvents are often used in nuclear magnetic resonance spectroscopy .
Samples were prepared by dissolution in deuterated chloroform (CDCl 3), deuterium oxide (D 2 O), or deuterated dimethylsulfoxide (DMSO-d 6). [5] Each spectrum is accompanied by a list of peaks with their respective intensities and chemical shifts reported in ppm and in Hz. Most spectra show the peak assignment.
Where small signals are observed in a 1 H NMR spectrum of a highly deuterated sample, these are referred to as residual signals. They can be used to calculate the level of deuteration in a molecule. Analogous signals are not observed in 2 H NMR spectra because of the low sensitivity of this technique compared to the 1 H analysis. Deuterons ...
While 1D NMR is more straightforward and ideal for identifying basic structural features, COSY enhances the capabilities of NMR by providing deeper insights into molecular connectivity. The two-dimensional spectrum that results from the COSY experiment shows the frequencies for a single isotope, most commonly hydrogen (1 H) along both axes.
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