1
|
Hello all, I have spent approximately 4 hours trying to analyze an H NMR consisting of two doublets of doublets (peaks at 8.0 and 6.9) and two triplets (peaks at 3.8 and 2.6). The doublets of doublets each contain 2 H's and the triplets each contain 3 H's making the ratio 2:2:3:3. The molecular formula for the molecule is C9H10O2 and C NMR show 7 peaks (24, 58, 117, 131, 132, 165, and 198) I have been working so hard on this but cannot seem to come up with a structure to fit the NMR. I can't seem to get two triplets each with 3 equivalent H's without a quartet. If anyone has some tips and could share it would be so much appreciated. |
|
1
|
IF C9H10O2 is the empirical formula and not the molecular formula, then the most likely explanation of the two triplets is that you have three chemically equivalent copies of X-CH2-CH2-Y. If X and Y are not identical, you would expect two triplets with area 3x(2:2)=6:6 which is a multiple of 3:3. (IF the areas are reliable ... Were the spectra acquired with adequate relaxation delay?) The doublet of doublets is probably due to an aromatic or heteroaromatic with C2 symmetry. |
|
0
|
It is always difficult to answer this sort of question when you don't actually see the spectrum (for example, what are the couplings, are there any fringy bits around the base of the peaks, are the triplets roofed towards each other, etc.) Perhaps a bit more information would help on this one... I took screen shots of the spectra but it wont allow me to upload them for some reason. Can I email you the spectra by any chance? If you don't want me to its ok. I tried to put them on facebook and post a link since thats the only other way I could think to do it but I don't think that will work - Kelsey O'Dell (Mar 14 '11 at 09:08) |
|
0
|
Hi Kelsey, you can actually post an image of your spectrum right into your question (which you can edit too). The editor has the image upload button. - Evgeny Fadeev (Mar 15 '11 at 01:25)
Oh, it was because your "karma" was below the required threshold to upload images - you could not post one. Now you should be able to. - Evgeny Fadeev (Mar 15 '11 at 01:28)