Question

I'm trying to analyze an IR specta but I'm having some trouble. I see a weak, broad peak at 3421.40 which is in the N-H, O-H area. Since I know the molecule I know it can't be N-H but could it be O-H despite being weak instead of strong?

Answer 1

What is the compound you're trying to analyze?

Can you post the IR spectrum you obtained?

Answer 2

It was from a reaction of phenylmangesium bromide with 2-heptane in THF followed by ammonium chloride.

Answer 3

the band at 3421 is the O-H stretch of water

Answer 4

I guess it's also possible for it to be the O-H stretch at the benzylic position

Answer 5

This is the IR spectrum of your molecule
http://webbook.nist.gov/cgi/cbook.cgi?ID=C614540&Mask=80

Answer 6

But in terms of your question, yes it's possible that the instruments response made the O-H stretch band less prominent than expected.

Answer 7

It's reassuring to know my spectra looks similar to what it should be. I don't see where else the OH should be so I suppose I'll report it as 3421 (w, O-H) Thank you for the input and spectra!

Answer 8

No problem, glad I could help !

Answer 9

One last question. I noticed the IR you posted is the same as my molecule minus the methyl on the 1st carbon. Is the product I drew wrong?

Answer 10

oh right, you meant 2-heptanone.

I didn't notice that methyl off the alpha carbon, but your structure is correct.

The structure i posted is significantly close, so the spectrum will be almost identical, but let me see if i can find it.

Answer 11

So i couldn't find the actual spectrum of your molecules, but i found a paper that showed the IR peaks (it's highlighted in yellow).

You could cite and compare these to your spectrum in your report

Answer 12

Ah, I hadn't noticed the typo. Sorry about that. I'll definitely look into using it in my report. Thanks for taking the time to help me!