15.3.1 Infrared spectroscopy
The C-O stretch of ethers is found around 1000-1200 cm-1 and is usually a fairly strong peak. It is sometimes difficult to see this peak because it is in the fingerprint region and may be overlooked. Also, remember that alcohols also have a C-O bond, but alcohols also have the very strong, broad peak for the O-H at 3300 cm-1 where ethers do not.
15.3.2 1H and 13C NMR
Protons on the alpha carbon appear around 3-4ppm in the 1H NMR. They are slightly deshielded by the electronegative oxygen atom. The alpha carbon atoms appear around 60-90 ppm because they too are deshielded by the oxygen.
In the 1H NMR of ethyl ether, the protons next door to the oxygen atom show up at 3.5 ppm in the spectrum. Those protons on the methyl group appear further upfield around 2 ppm.
In the 13C NMR spectrum for ethyl ether, the carbon atom next to the oxygen atom appears around 85 ppm in the “next to something special (50-100)” range.
Mass Spectrometry
A common bond cleavage in mass spectrometry is between the alpha and beta carbon atoms. This fragmentation makes the alpha carbon atom a carbocation. This carbocation can be stabilized through resonance with the lone pair of electrons of the oxygen atom.
