[surviving]

I have the Mass Spec, NMR, and IR of each, but I'm having lots of difficulty simply analyzing the mass spec

Here is the first:
IR:

NMR:

MS:

I think the main trouble I'm having is really how to decipher a mass spec. I know you start with the rule of 13 first, then look to see if the nitrogen rule applies, perhaps substitute an oxygen for a carbon + 4 hydrogens, calculate IHD for those formulas you find and then check for any isotope discrepancies...but beyond that, I really have no clue.


Second:
IR:

NMR:

MS:

I've been trying to decipher these for a week now with no luck. My instructor tells me to give it my best effort based on the given data, but I can't seem to get anywhere. Any help leading me in the right direction, or more better, explaining how I should go about doing this and other spectra in the future, would be immensely helpful. Thanks!

[Dynamo22]

I'm not fantastic at NMR, IR, etc. I haven't done mass spec yet. But the first one appears to be a carboxylic acid.  The 1694 stretch would represent the C=O of the carbonyl. Anything below 1500 is usually single bonds. I think you figure out the chemical formula of them, it will make it much easier. I'm sorry I can't help with that at the moment. The second one seems to be an alkane, I'm not seeing much else in the IR to indicate otherwise.

As far as going about solving these problems, I usually draw a line at 1500 on the IR spec (although our professor usually just gives us numbers which sucks cause you can't see the trends of the functional groups), anything below this usually is just single bonds and its referred to as the "fingerprint region". Above that is where you get the goods. Double bands fall between 1650-1850. Triple bonds are in the 2100-2300 range. Bonds to hydrogens are very high, usually 2700 on up. Qualitatively knowing what specific functional groups look like will help you very much. There should be plenty of resources online to help you with that (Klein's Organic Chemistry as a Second Language 2nd Semester Topics helps very much with this).

Proton NMR is your bread and butter. But you need to know your degrees of unsaturation. If you don't know that you most likely won't solve the problem when drawing the structure.  Proton NMR is the best way to identify the structures but its the hardest for me to remember. Knowing the shifts and the effects of electronegative atoms can get a little tricky. Again, knowing your degrees of unsaturation, using your qualitative information from NMR and IR can get you pretty far.

Sorry I don't have more to offer, I'm currently hammering the spectroscopy stuff into my head as we speak!

[surviving]

Well, given the NMR information, the first one most definitely cannot be a carboxylic acid. A carboxylic acid proton gets shifted way farther downfield than most other protons in the 10-13 region. Sooo unfortunately, :x.

My theory is that it's some sort of alkene? But I don't know.

[curiouscat]

Any idea about the molecular weight?

[surviving]

Any idea about the molecular weight?

Using the Mass Spec info, 112 and 223 respectively.

[MOTOBALL]

MS of Cmpd. 1A

---low intensity of ions below m/z 149 is consistent with aromatic character
---m/z 149 is STRONGLY indicative of a phthalate (these are widely-occurring plasticizers)
---loss of 46 Da from m/z 223 to 177 is possibly due to -NO2 group (or CO + H2O)
---if m/z 223 IS Mol. ion, then has ODD number of N atoms (1, 3, 5 etc)

The Mol. Ion is the single most important ion in a spectrum.

If m/z 223 is NOT mol. ion, then it has been formed by loss of a small radical or neutral
--- MW is then 223 + for example, 15 (CH3) or another radical/neutral; this would give MW 238 Da, and an EVEN MW requires an EVEN (0, 2, 4 etc) N count. 

[NotExactly]

I'm not fantastic at NMR, IR, etc. I haven't done mass spec yet. But the first one appears to be a carboxylic acid.  The 1694 stretch would represent the C=O of the carbonyl."

16-1700 can also be C=C, which it is in this case.  The only type of carbonyl that falls below 1700 is typically an amide.