[ron09c]

Hey guys! Can somebody pls explain the peaks at <2000 cm-1 in the IR spectrum of isopropylbromide (see Figure below)? Thanks in advance!

[Dan]

You must show you have attempted the question, this is a Forum Rule.

[ron09c]

Sorry, I'm not quite familiar with the forum rules yet. Anyway, what I cannot figure out are the strong peaks at 1230 and 1170 cm-1 and medium bands at 1050 and 900 cm-1. Also, I'm not familiar with what produces the doublet at 1500 cm-1. The doublet in 1400 cm-1 produced by the geminal methyl groups of the isopropyl is overlapped. What vibration produces the overlapping signal? I'm hoping for your fast response guys; assignment is due tomorrow..Thanks 

[Archer]

I fear that you may have left this a bit late if it's due in tomorrow. I am not sure that anyone here is willing to do your homework for you.

E.M. Forster once wrote

Spoon feeding in the long run teaches us nothing but the shape of the spoon.

You should be able to answer this problem yourself if you understand the theory behind the analytical technique. If you can't answer the questions below then you will need to hit the books again otherwise you won't know if a similar question comes up in an exam and we are not there to help you.


Can you explain how IR signals are produced?

What primarily dictates where a peak will appear in the spectrum?

Why are the vibrations for triatomic molecules more complex than those for diatomic molecules?

[ron09c]

Hopefully, the prof won't give a secondary isopropyl halide for this kind of problem in the exam. The textbooks that I have studied haven't tackled spectrum identification for this kind of compounds. I have an answer for this problem and submitted it earlier. I'm just not sure what causes the medium strong and strong peaks between 1300 and 800 cm-1. Can anybody give a definite explanation of what produces the IR peaks at this region? Thanks for the comments guys, next time I'll be more familiar with rules and traditions here..