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Unread 05-27-2003, 07:58 AM
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Default Answered: Does NMR coupling occur between equivalent protons?

for example, in 1,4 dioxane, do the HNMR signals show up as singlets or triplets?
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Best Answer - Posted by Cubbi1242
NMR coupling occurs between equivalent protons, but regular NMR spectra are not sensitive to this coupling, because under the conditions of the experiment, spin transitions that would reveal it are forbidden by symmetry, and the signal appears as a singlet.That's also why CH2 and CH3 groups typically appear as singlets, even though geminal H-C-H coupling constant is quite large, 14-18 Hz.All 8 protons in 1,4-dioxane have the same chemical shift, and thus show up as one singlet at 3.692 in CDCl3 or 3.757 in D2O.
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Default Does NMR coupling occur between equivalent protons?

1,4-Dioxane has a single peak at 3.70 ppm.
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Default Does NMR coupling occur between equivalent protons?

NMR coupling occurs between equivalent protons, but regular NMR spectra are not sensitive to this coupling, because under the conditions of the experiment, spin transitions that would reveal it are forbidden by symmetry, and the signal appears as a singlet.That's also why CH2 and CH3 groups typically appear as singlets, even though geminal H-C-H coupling constant is quite large, 14-18 Hz.All 8 protons in 1,4-dioxane have the same chemical shift, and thus show up as one singlet at 3.692 in CDCl3 or 3.757 in D2O.
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