Q11P - Organic Chemistry (Mcmurry)

Question

Where might the following compound have IR absorptions?

Step-by-Step Solution

Answer

Absorption bands seen at 2210-2260 cm^-1 , 1690 cm^-1  and 1640-1680 cm^-1 .

Absorption spectrum

Absorption spectrum indicates dark lines presence in spectrum when radiation transmitted through a substance indicating absorption at specific wavelengths of electromagnetic radiation.

Chart for absorption by specific functional group

The given chart has values for absorption of particular wavelength radiation by specific functional group.

Functional groups present in given compound

Here three functional groups are present namely alkene, nitrile group and ketone group. Red atom indicated here is oxygen and blue atom is nitrogen according to book. 

Absorption bands in a spectrum

Here three absorption bands will be seen:

• Nitrile group absorption band is seen at 2210-2260 cm^-1.
• Ketone group absorption band is at1690 cm^-1. This lower value is due to the presence of the ketone group nextto the double bond.
• Alkene group - C = C -band at1640-1680 cm^-1.