[oscillate_wildly]

Hi,

I am really struggling to use different spectroscopic methods to work out this unknown compound.

I have had to carry out ¹H NMR, ¹³C NMR, mass spectroscopy, IR, and a combustion analysis.

From the combustion analysis I have worked out the empirical formula to be: C₈H₇NO₄   

And from the mass spectrum, I have only been able to determine that the compound contains a benzene ring and that the fragment 15 is CH₃, 46 is NO₂ and the 59 - CH₃COO.

This is where I am stuck. I cannot seem to piece together the compounds' structure.

Here are the relevant links for the spectroscopy I carried out:

Mass spectrum: http://tinypic.com/r/2r3i39v/7
¹³C NMR: http://tinypic.com/r/30w2zpu/7
¹H NMR: http://tinypic.com/r/2i6gpz4/7
IR: http://tinypic.com/r/v3n0y0/7

High resolution scans (6.87 MB) : http://www.mediafire.com/?t2828evy8e709wl

Any help would be greatly appreciated!

Thank you!

[fledarmus]

So you have a benzene ring, a nitro group, and a methyl ester. Now all you have to do is figure out whether they are ortho, meta, or para.

[oscillate_wildly]

Thank you for the reply.

How would I go about doing this?

Thanks again.

[fledarmus]

At one time I used the fingerprint region in the IR. Almost any table of IR resonances will have it listed. If you don't have one, try this:

http://www.muhlenberg.edu/depts/chemistry/irexer/IRDATATB.htm

With better NMRs though, I find it easiest to look at the splitting patterns of the aromatic protons. What sort of splitting pattern would you expect to see from ortho, para, and meta substitution? Keep in mind that the para substitution leads to symmetry. For simplicity, start by considering only splitting from adjacent protons.