Question

Can someone label all functional groups for the Ir peaks for these two? Thanks

%Transmittance 4000 LO 3500 181 Sat Oct 19 08:44.04 2019 (GMT-04:00) 3000 3060.48 3027.71 2990.90 2813.61 2742.06 2500 Wavenumbers (cm-1) 2000 Liquitos 1683.06 1625.411605.01 1575.19 1449.62 1500 1392 54 327.58 1250.78 1203.13 1305 58 1293.93 1178.00123.92 100567 1072 18 1000 972.77 748.10 688.80 605.65 582.83

Answer 1

1.

IR Spectra : Major peaks

• 3300-3400 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).
• 3060 ; 3027 cm-1 (medium) : this is probably due to (sp²) =C-H stretching, it may be due to presence of aromatic ring (benzene) or alkene .
• 2813 ; 2742 cm-1 (medium) : Two medium intensity peaks 2830-2700 cm^-1, due to 'Aldehyde C-H​​​​​​​' indicates presence of aldehyde functional group.
• 1684 cm-1 (strong) : Indicates presence of Carbonyl group (C=O) ; it may be due to Aldehyde carbonyl attached with aromatic ring or -C=C- group.
• 1625 cm-1 (strong-medium) : -C=C- stretching
• Below 1500 cm-1 is fingerprint region of spectra, which complex to interpret .

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2. This spectra have all peaks with weaker intensity than usual spectrum ; it indicates impure sample or error in recording spectra. Interpreting such spectra with certainity is not possible, an attempt to identify diagnostic peaks has been made :

IR Spectra : Major peaks

• Very Broad peak 3300-2600 cm-1 : due to -OH of -COOH group.
• two peaks in 2300-2100 cm-1 region assures for presence of alkyne (cabon -carbon triple bond
• Peaks at 1712 cm-1 and 1682 cm-1 indicates presence of Carbonyl group (C=O).
• Peak ~1150 cm-1 is amy be due to 'C-O' stretching.