Question

identify all important peaks of the IR spectra.

KE 3500 3406.37 3000 2957.02 2872.59 2722.68 2500 Wavenumber cm-1 2000 1712.74 1500 1468.24 1407.99 1385.27 1366.91 1334.58 1294.48 1219.99 1169.20 1148.98 1125.44 1041.89 944.87 923.15 894.71 839.63 mill 1000

Answer 1

IR Spectra : Major peaks

• 3406 cm-1(weak) : this is probably due to '-N-H' stretching : single peak in this region indicates secondary Amine -NH-. (-NH bands are weaker and narrower than corresponding -OH bands).
• 2957 ; 2872 cm-1 (strong) : this is probably due to Alkyl (sp³) C-H stretching, its intensity relative to other peaks indicates larger size of the alkyl group.
• 1712 cm-1 (strong) : Indicates presence of Carbonyl group (C=O) ; It may be due to carbonyl of ketone.
• Below 1500 cm-1 is fingerprint region of spectra, which complex to interpret and have little diagnostic role during initial structural determination.