HIGH RESOLUTION NMR SPECTRA

Equivalent hydrogen atoms Hydrogen atoms attached to the same carbon atom are said to be equivalent. Equivalent hydrogen atoms have no effect on each other - so that one hydrogen atom in a CH2 group doesn't cause any splitting in the spectrum of the other one. But hydrogen atoms on neighbouring carbon atoms can also be equivalent if they are in exactly the same environment. For example: These four hydrogens are all exactly equivalent. You would get a single peak with no splitting at all. You only have to change the molecule very slightly for this no longer to be true. Because the molecule now contains different atoms at each end, the hydrogens are no longer all in the same environment. This compound would give two separate peaks on a low resolution NMR spectrum. The high resolution spectrum would show that both peaks subdivided into triplets - because each is next door to a differently placed CH2 group. Where would you like to go now? To the NMR menu . . . To the instrumental analysis menu . . . To Main Menu . . . © Jim Clark 2000