Quantcast

1h Nmr & 13c Nmr

This forum made possible through the generous support of SDN members, donors, and sponsors. Thank you.

ToothDoctor

Member
7+ Year Member
15+ Year Member
Joined
Aug 9, 2002
Messages
30
Reaction score
0

Members don't see this ad.
Hi...I'm new here! Could someone please help me out here?!?! I'm completely lost when it comes to figuring out how many peaks (and whether they are singlets, doublets, etc.) a certain molecule gives for 1H NMR. I'm equally lost when it comes to 13C NMR. I have read the Kaplan book over and over again and it seems greek to me. Does anyone have a clear simple explanation with a couple of examples? I appreciate it...Thanks.
 

ItsGavinC

Full Member
Moderator Emeritus
20+ Year Member
Joined
Oct 7, 2001
Messages
11,749
Reaction score
23
I don't have time for any explanations right now, but I can tell you that the odds of having any C NMR on the DAT are slim to none (I don't think I've ever heard of a question with C NMR!). There's a better chance of having H NMR, although I didn't have any of those either on my DAT.
 

vixen

I like members
10+ Year Member
15+ Year Member
Joined
Oct 17, 2000
Messages
5,760
Reaction score
1
here's a quick ex:


if you have R----CH2-CH3

the h's on the ch3 are equivalent....therefore, they will all get the same splitting pattern...look 1 c away from them and how many H's do you see? 2 so 2=n and N+1=3 so its a 3H triplet. The CH2 has its n=3, so n+1=4 so its a 2H quartet.....

if you had

CH3-CH2-O-CH2-CH3

the two methyl groups are equivalent here (equivalent meaning they're in the same chemical environment....right next to a CH2 and then and O) so the methyls would get One big splitting pattern of: 6h triplet

the ch2's are also equal so they'd be a 4H quartet...

hope this helps :)
 

ToothDoctor

Member
7+ Year Member
15+ Year Member
Joined
Aug 9, 2002
Messages
30
Reaction score
0
Hey thanks! That does help! What happens if there in no adjacent carbon? For example.... CH3-O-CH3?
 

vixen

I like members
10+ Year Member
15+ Year Member
Joined
Oct 17, 2000
Messages
5,760
Reaction score
1
CH3-O-CH3 would be a 6H singlet....n=0 here so n+1=1...singlet!
 
Top