Unformatted text preview: =C-H bond stretching). The terminal alkyne can be eliminated since there is no absorption near 3300 cm –1 (corresponding to the acetylenic ≡C-H stretch). The only reasonable choice is circled – the C ≡C triple bond stretch does not appear near 2200 cm –1 because this vibration is often IR inactive for internal alkynes! The strong, broad absorption centered near 3400 cm –1 indicates the presence of a hydroxyl group, eliminated the choice at the top left. The absence of any absorptions in the range between 1500 and 2000 cm –1 suggests that there is no carbonyl group present (eliminating the carboxylic acid), nor is there an alkene double bond present (eliminating the choice on the bottom right). By process of elimination, the circled choice appears to the only reasonable one!...
View Full Document
- Summer '08
- Functional group, Infrared, Aldehyde, acetylenic C-H stretch, bond stretch