Use arguments based on resonance and electronegativity effects to explain the trend in
Chapter 2, Problem 2.28(choose chapter or problem)
Use arguments based on resonance and electronegativity effects to explain the trend in carbonyl IR stretching frequencies from higher frequency for esters and carboxylic acids to lower frequencies for amides. (Hint: Use the range of carbonyl stretching frequencies for aldehydes and ketones as the base frequency range of an unsubstituted carbonyl group and consider the influence of electronegative atoms on the carbonyl group and/or atoms that alter the resonance hybrid of the carbonyl.) What does this suggest about the way the nitrogen atom influences the distribution of electrons in an amide carbonyl group?
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