Reading nmr

The Ar the left means arene right??
Arene means a benzene ring??

Another q, there is a box stating
H-C-C=O
Aldehyde
Ketone
Ester
Amide
Acid

What do they mean ? Cause I suppose there is many H atom in a aldehyde molecule ? What H atom it is refering to??

Thank you!
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(edited 9 years ago)

Reply 1

Atomantium Claws

Arene means any aromatic, but yeah it's usually benzene in that region.

There are other aromatics with more/less than 6 carbons in the ring (so not really a benzene equivalent) but they are less common and often have a wider range of chemical shifts.

E.g. Cyclo-octa-tetra-ene has 8 carbons in the ring but is also aromatic/ arene.

Reply 2

Pigster

H-C-C=O refers to one or more hydrogens attached to a carbon. That carbon is attached to another carbon, which has a double bond to an oxygen.

Propanal, CH3CH2CHO has three H environments, from left to right

shift = 0.2-1.8 H-C-C
shift = 1.7-3.0 H-C-C=O
shift = 9-10 H-C=O (not on your chart!)

Reply 3

Lamalam

Original post by Pigster

do you mean that the box is actually referring the hydrogen on H-C-C=O, and this "structure" may appear in aldehyde, ketone, acid, ?

Reply 4

Pigster

In all structures that have a H attached to a carbon, which is adjacent to a C=O, then you'll get a peak with a shift value about there. There are other functional groups with C=O in, but the three you state are included.