Sort the pairs of related compounds by their carbonyl stretching frequencies in cm–1. (There will be three compounds per bin.)

Bin # 1: Slightly higher
Bin #2: Slightly lower

Compounds:
-butanol
-but-2-enal
-heptan-3-one
-hept-4-en-3-one
-cinnamaldehyde
-3 phenylpropanal