Quadrupolar broadening relaxation

The resonance frequencies of the isotopes Mo and Mo are very similar, differing by only 2%, but the sensitivity of Mo and its significantly smaller second-order quadrupolar broadening make it the preferred Mo NMR nucleus even though Mo has the advantage of relaxing much faster in cases where quadrupole relaxation is dominant. 

In 207p j Of jfj X NMR spectra, the observation of indirect nuclear oipb-X spin-spin coupling may be affected by fast relaxation either of the ovpb or of the X nucleus (see Fig. 4 for X = "B with moderately fast quadrupolar spin relaxation ). The broadening of o pb satellites in X NMR spectra, recorded at high field strength Bq, may indicate highly anisotropic surroundings of the o Pb... 

The signal from H(3) is broadened because N-H(3) spin coupling is not completely washed out by quadrupolar relaxation of the nitrogen atom (68MI41701>. This broadening niay be useful in assigning signals in the spectrum and it is usually reduced in solvents of... 

Other good news comes in the shape of the 13C nucleus having a spin quantum number of /2. This means that 13C signals are generally sharp as there are no line-broadening quadrupolar relaxation issues to worry about and we don t have to deal with any strange multiplicities. 

The exchange of the coordinated aqua ligand of the W(IV) aqua oxo species was qualitatively studied by NMR line-broadening as a function of temperature based on Eq. (26), where the transverse relaxation time of the bound oxygen-17 nucleus is given by 1/T2b. The l/T2Qb represents the quadrupolar relaxation rate and kmi the chemical exchange rate constant... 

MHz relative to the protons in Mc4Si at exactly 100 MHz. The effect of quadrupole line broadening is attenuated to some extent by the magnitude of / (/= 9/2), and the line widths are among the narrowest of all quadrupolar nuclei studied to date. One would expect efficient relaxation via the quadrupole moment, giving very short T2 times and consequently broad NMR signals. Also if the electronic distribution around the nucleus is symmetrical, sharp resonances can be obtained. 

Both [14N1- and [lsN]-pyrrole have been subjected to extensive analyses in the pursuit of accurate f3C chemical shifts and heteronuclear coupling constants. The resonance due to the a-carbons in [14N]pyrrole is broadened as a consequence of non-zero coupling to, and quadrupolar relaxation by, the 14N nucleus. 

The H NMR spectra of the 1,3,5-triazines are quite simple. The ring protons give sharp lines which are not broadened by nitrogen quadrupolar relaxations (65BSB119). The chemical shifts of the ring protons are 1 to 2 p.p.m. downfield from benzene protons, presumably... 

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