Snlittins in rH NMR So far we've seen that the electronic environment around a given proton nuclei will affect its chemical shift but we also must consider the magnetic dipoles created by the spinning protons on adjacent carbons. This Qpe of interaction is lcnown as spin-spin coupling. Recall that in a strong magnetic field these adjacent protons are aligned (c-spin state) or opposed (|3-spin state) to the applied magnetic field. If the magnetic dipole of an adjacent proton is aligned with the applied magnetic field the proton of interest will feel a stronger magnetic field. Conversely, if the magnetic dipole is opposed to the applied magnetic field, the proton of interest will feel a weaker magnetic field. Recall that the probability the magnetic dipole of a given proton is aligned or opposed to the applied magnetic field is essentially equal. See the example below. For bromoethane there are two inequivalent sets of protons (methyl and methylene). Consider the effect of the spin of the individual methylene protons on the methyl
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This note was uploaded on 12/27/2011 for the course CHEM 281 taught by Professor Williams during the Fall '11 term at Simon Fraser.