Nuclear Magnetic Spectroscopy

Nuclear magnetic resonance gives information about the relative number and position of hydrogen atoms in a molecule.

Proton n.m.r. spectra are obtained using samples dissolved in proton-free solvents (e.g. deuterated solvents and CCl4).

Chemical shift, ? , is measured next to a standard tetramethylsilane (TMS).

The chemical shift of an individual proton depends on the molecular environment.

The area under the individual peaks on a proton n.m.r spectrum are proportional to the number of protons with that chemical shift.

N.m.r can tell us the number of different types of protons and how many of each type of proton there are.

In addition there is an interaction between protons on adjacent carbons called spin-spin coupling, which leads to a splitting pattern.

If a peak is split into two there is one proton on the adjacent carbon, if it is spit into three there are two protons on the adjacent carbon.

This is called the n+1 of spin-spin splitting.

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