Another BS NMR question

[Luthertaketwo]

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http://www.chem.ucla.edu/cgi-bin/webspectra.cgi?Problem=bp15

This PNMR doesn't seem right. Shouldn't the PNMR show 3 singlets, 1 doublet, 1 triplet if their "supposed solution" is correct? The only way you would have got that answer is if you "ran with the CNMR" and ignored the PNMR. That's ******ed.

 

[acab]

The 2 Hs on Cs adjacent to the C attached to the Br are more deshielded so are further downfield. So those 2 Hs shouls show s triplet further down. The other 2 Hs on the ring father from the C with Br should show a triplet a bit more upfield from the previous triplet. Finally the 3 Hs on the CH3 show 1 peak way upfield.

Main point: the 4 Hs on the ring are not equivalent. The closer to an electronegative element, the more deshielded the h will be.

Hope this answers your questions.

 

[Luthertaketwo]

Originally posted by acab
The 2 Hs on Cs adjacent to the C attached to the Br are more deshielded so are further downfield. So those 2 Hs shouls show s triplet further down. The other 2 Hs on the ring father from the C with Br should show a triplet a bit more upfield from the previous triplet. Finally the 3 Hs on the CH3 show 1 peak way upfield.

Main point: the 4 Hs on the ring are not equivalent. The closer to an electronegative element, the more deshielded the h will be.

Hope this answers your questions.

Not exactly. Heh. How can "those 2 Hs shouls show s triplet further down"when one doesn't even have any vicinal hydrogens and the other has only one(should be a doublet)? Er. It should be a triplet, a doublet, and 3 singlets.

 

[Luthertaketwo]

UCLA = suq?

 

[Luthertaketwo]

Hrmm. I guess so.