Do we have to memorize the chemical shifts in proton NMR

[inaccensa]

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Have you guys memorized these shifts. I understand how the NMR works, but the shifts are so similar, its difficult to decipher anything based on that.

If the protons are heavily shielded by electron donating atoms, then they tend to be upfield and if they are surrounded by electron withdrawing groups, they are found downfield at a lower magnetic field. Additionally, if chemically equvivalent protons are surrounded by lets says 3 protons, you follow the n+1 rule & you will find 4 peaks.

But what is the significance of intensity of these peaks.

They keep talking about the area under the peaks, how do you determine that.

It is needless to say that I kept ignoring this section.

 

[RogueUnicorn]

yes the shifts are important to know.

the area under the peaks correspond to the number of protons giving off that signal.

 

[thebillsfan]

here's the shirts i memorized

aldehyde 9-10
acid 10-12
aromatic 6-8
most everything else is in the 1-5 range so its hard to discern between them.

anything else anyone wanted to add to the list?

ir spectra is a little more extensive

 

[RogueUnicorn]

also know deshielding (i.e. electronegative) groups will shift downfield by a couple.

IR is qute easy actually, just know OH NH and C=O

 

[SuperSaiyan3]

here's the shirts i memorized

aldehyde 9-10
acid 10-12
aromatic 6-8
most everything else is in the 1-5 range so its hard to discern between them.

anything else anyone wanted to add to the list?

ir spectra is a little more extensive

vinyl groups (next to double bonds) are 5-6.

That's pretty much all you need to know... I find that aldehydic protons are the ones tested the most.