Seem to be really struggling with carbon nmr, can do straight line compounds very easily but when it comes to aromatic compounds can never seem to get it. So for example the molecule below what steps would I need to go through to get the correct number of carbon environments, is there a definitive method or not, I always seem to be getting 6?? Thanks in advance!
Seem to be really struggling with carbon nmr, can do straight line compounds very easily but when it comes to aromatic compounds can never seem to get it. So for example the molecule below what steps would I need to go through to get the correct number of carbon environments, is there a definitive method or not, I always seem to be getting 6?? Thanks in advance!
In general, you should be looking for symmetries that let you exchange different carbons. In the given example you can draw a line of symmetry across the ring, passing between the two substituted carbons, which should help you see which carbons are equivalent.
In general, you should be looking for symmetries that let you exchange different carbons. In the given example you can draw a line of symmetry across the ring, passing between the two substituted carbons, which should help you see which carbons are equivalent.
Benzene is perfectly symmetrical and has only one environment.
Methylbenzene has a plane of symmetry passing through the methyl and dividing the ring into two identical halves. It has 5 equivalent carbon environments and four equivalent hydrogen environments.
1,2-dimethylbenzene has a plane of symmetry passing between the two methyl substituents. It now has four carbon environments and three hydrogen environments
2-chloromethylbenzene does not have a plane of symmetry and has 7 different carbon environments and 5 different hydrogen environments.