IR Spectroscopy Signals

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Single Bond: O-H

3200-3600 (broad)

Single Bond: Carboxylic Acid O-H

2200-3600 (very broad)

Single Bond: Amine

3350-3500

Single Bond: Triple Bond C-H (sp)

~3300

Single Bond: Double + Single Bond C-H (sp²)

3000-3100

Single Bond: 3 Single Bonds C-H (sp³)

2850-3000

Single Bond: Double Bond to O, Single Bond C-H Aldehyde

2750 and 2850 (two weak signals)

C=O Double Bond: Anhydride

~1820 and ~1760

C=O Double Bond: Acyl Chloride

~1790

C=O Double Bond: Ester

~1735 (can’t differentiate from aldehydes, ketones, carboxylic acids)

C=O Double Bond: Aldehyde

~1730 (can’t differentiate from esters, ketones, carboxylic acids)

C=O Double Bond: Ketone

~1720 (can’t differentiate from esters, aldehydes, carboxylic acids)

C=O Double Bond: Carboxylic Acid

~1715 (can’t differentiate from esters, aldehydes, ketones)

C=O Double Bond: Amide

~1650

If the C=O bond is conjugated, will the frequency (cm^-1) be lower or higher?

Lower, since the resonance structures give the compound more single-bond character

Double Bonds: C=O

~1650-1820 (strong)

Double Bonds: C=C

1600-1700

Double Bonds: Benzene/Aromatic Rings

1450-1600 (peaks for the C=C bonds) and 1650-2000 (overtones, combination bands)

Triple Bonds: C≡C

2100-2200

Triple Bonds: C≡N

2200-2300

Amines: Primary

3350 and 3450

Amines: Secondary

3350-3500

Double Bonds Region

1600-1850

Triple Bonds Region

2100-2300

Z-H Bonds Region

2700-4000