When doing 1H-NMR, what is the chemical reason why an the hydrogen in an OH group
sometimes shows up at different ppm locations? For propan-2-ol, I found a doublet at 4.88ppm,
which makes a lot of sense due to the n+1 rule, but some of the literature values show singlets,
sometimes at different ppm values, and some literature does not show a peak for this hydrogen at
all. My lab report requires that I explain what molecular interactions are responsible for this
phenomenon. Thank you!
Solution
The oxygen in OH gp cause the shielding of protons and thus a diiferent ppm location is shown
by OH .
Hence this behaviour is due to the shielding and dishielding phenomenon of proton NMR .