[nj_bartel]

 http://img227.imageshack.us/my.php?image=nmrquestionvi8.jpg

We're learning introductory NMR in Organic I, so I've been practicing interpreting real NMR spectra with a given chemical formula to determine the structure.  For compounds like the one I linked to, it seems like the spectra come out with H₂ and H₃ being electronically identical, but based on what I've learned, there's no reason for this to be so.  Would H_1-3 & H_2-4 W-coupling (something I know of, but we haven't learned about) explain this?

This is one of the spectra  in question that seems to be that way

 http://www.chem.ucla.edu/cgi-bin/webspectra.cgi?Problem=bp2&struct=on

Thanks.

[nj_bartel]

 

[nj_bartel]

darn you nmr noobs! 

[ATMyller]

Its hard to say for sure without the actual integral values, but with o-Anisaldehyde 2-methoxybenzaldehyde there seems to be only 3 aromatic peaks and judging from the intergal plots there seems to be one peak with two overlapping aromatic signals. Even the the electronic shielding is different the difference might be smaller than e.g. the 3j(H-H) coupling which results in a single multiplet rather than two separate signals.

[macman104]

Look up o-Anisaldehyde on:

http://riodb01.ibase.aist.go.jp/sdbs/cgi-bin/cre_index.cgi?lang=eng

You'll see it marks a range for two of the hydrogens.  Consequently, those 2 can participate in w-coupling I believe.

[nj_bartel]

Thank you, why don't b and d have that same effect as well though?