IR Spectroscopy

What does IR (infrared) do to molecules

causes molecules to vibrate

When is IR absorbed my molecules

when the bonds are polar and is not symmetrical

Degrees of Unsaturation

(2(number of carbons) + 2 + (number of nitrogens) - (number of hydrogens) - (number of halogens))/ 2
Or number of pi bonds + number of rings
Triple bonds count as two pi bonds

At the 3400-3200 region what are the shapes

Smooth tongue
Vampire fangs
Single fang
Beard

Smooth tongue indicates

alcohol

Vampire Fangs indicate

primary amine

Single fang

secondary amine or terminal alkyne

Beard indicates

carboxylic acid

signal at 1810 and/or 1760

anhydrides

signal at 1800

acid chlorides

signal at 1735

esters

signal at 1725

aldehydes

signal at 1715

ketones

signal at 1710

acids

signal at 1690

amides

small signal at 2200

triple bond present C≡N or C≡C

signal to the left of 3000

Indicates there is a double bond