Quick Question about H' NMR

[el.harpo]

I'm just going over this stuff for the first time in my life and I was wondering... is a singlet more shielded (and therefore more upfield) than a doublet, which is more shielded and more upfield than a triplet. Also, are multiplets the most deshielded and downfield than anything else?

Thanks.

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[BigRedPremed]

I'm just going over this stuff for the first time in my life and I was wondering... is a singlet more shielded (and therefore more upfield) than a doublet, which is more shielded and more upfield than a triplet. Also, are multiplets the most deshielded and downfield than anything else?

Thanks.

Being a singlet/doublet/triplet has nothing to do with being more or less shielded. Resonances that appear further downfield are less shielded. Singlets/doublets/triplets tell you know many proton neighbors there are.

 

[NilamPatel]

deshielded is downfield and shielded is upfield. the closer you are to something that is electronegative, you are considered to be deshielded. If there are more than one EN things than you compare which one is more EN.

IE: CH3 - CH2 - CH2- Cl

The H's closet to the Cl are the more deshielded and the ones fartherst away are considered least deshielded, or i like to say shielded.

Splitting has to do with the neighbors of the protons you are looking at. So if you take the above example. The H's that are farthest from the Cl will have triplet splitting because the formula says you take the # of protons from the neighbor and + 1. Now the tricky ones are the middle H's. For those you add up the neighbors and then add one, so for above it would be 3+2 = 5 + 1..that makes it a multiplet.


i hope that cleared it up? i love orgo, i could talk about it for hours (im a dork i know) 🙂

 

[el.harpo]

i hope that cleared it up? i love orgo, i could talk about it for hours (im a dork i know) 🙂

Thanks guys. Makes perfect sense...I went over the book again and I had just read a small part of it wrong which was causing a lot of confusion. BTW, I love orgo [lecture] too, just never took the lab seriously 😎.