Question

organic chemistry: use structure to match with IR spectroscopy

2. Match the follow Match the following six compounds to the IR spectra shown below. Draw the structure in the box. on the spectra, mark all important peaks with arrows or circles, and label them with corresponding bonds. - C- CH.CH.CH Structure: Structure: Structure:

Answer 1

• Firstly let us start with the compound containg carbonyl group which are cyclohexanone and cyclohex-2-en-1-one.

And by seeing IR spectra we can see that peak of carbonyl group wich comes between 1650-1750cm-1 is in 2 spectra which is spectra no 2 and 4.

Now in spectra 2 there is one peak just near 3000 which is due to C-H stretch and this tells us that spectra 2 is of cyclohexanone it does not have any double bond so peak is only due to C-H stretching and spectra 4 is of cyclohex-2-en-1-one.

Structure: C-A

Structure: -Car

• Now as we see spectra 6, it has a prominent peak of OH near 3500cm-1, and the only group which has OH in it is cyclohexanol. So cyclohexanol has spectra 6.

AA Structure: 애

• Now for cyclohaxanamine it has one primary amine group whose peak should come at 3500cm-1 and by seeing spectra we come to know that spectra1 is appropriate for it.

• Now we are left with spectra 3 and 5 and the compounds left are diethyl ether and pent-1-yne.

For diethyl ether we need peak between 1100 - 1300cm-1which comes due to C-O-C asymmetric stretching and for pent-1-yne we need peak between 2100-2140cm-1 of C$\equiv$C.

So by seeing spectra we come to know that diethyl ether has spectra 5 and pent-1-yne has spectra 3.

Structure: 데 나 COC

Structure: I-CEC H[=[-CH=CH2
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