C13 NUCLEAR MAGNETIC RESONANCE (NMR)

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13C NMR C13 resonances occur from 0 to 200 ppm (δ). These peaks are split by the attached hydrogens. However, proton decoupled (broadband) spectra are not split by H.

Transcript of C13 NUCLEAR MAGNETIC RESONANCE (NMR)

  • C13 NUCLEAR MAGNETIC RESONANCE (NMR)

  • 13C NMR C13 resonances occur from 0 to 200 ppm ().

    These peaks are split by the attached hydrogens.

    However, proton decoupled (broadband) spectra are not split by H.

  • 13C NMR Distortionless enhancement by polarization transfer (DEPT) spectra permit identification of CH3, CH2, and CH carbon atoms.

    DEPT 45 shows 1o, 2o,and 3o carbons.DEPT 90 shows only 3o carbons.DEPT 135 shows 1o and 3o carbons as positive peaks and 2o carbons as negative peaks.

  • 13C NMR

    H1

    H environment, ppmH environment, ppm

    defined0Acetylenic~2.5

    Saturated carbonsAromatic~6.5-8

    primary~0.9

    secondary~1.3Ester3.5-4.5

    tertiary~1.6

    Acid10-12

    Olefinic carbons4.5-6

    4.5-6Aldehyde9-10

    4.5-6

    1.5-2

    2.5-41-5

    C13

    C environment, ppmC environment, ppm

    Saturated carbons0-55Acetylenic60-90

    primary4-30

    secondary12-50Benzenoid120-140

    tertiary22-54

    quaternary29-47Carbonyl150-220

    amides & imides150-180

    Olefinic carbons100-165esters & anhydrides155-185

    100-110acids170-190

    110-120ketones185-220

    125-150aldehydes190-210

    130-154

    140-165Nitriles115-125

    AlenesAzomethine145-165

    70-95

    200-215

    Sheet3

  • 13C Off-resonance decoupled spectrum

  • 13C Off-resonance & Broadband decoupled spectraBroadbandOff-resonance

  • 13C Broadband decoupled spectrum

  • 13C NMR n-HexaneBroadband

  • 13C NMR AcetoneBroadband

  • Broadband1H & 13C NMR: 1,1,2-trichloropropane

  • 1H & 13C NMR: 2-methyl-2-buteneBroadband

  • 1H & 13C NMR: 2-methyl-1-buteneBroadband

  • 13C NMR 6-methyl-5-hepten-2-olBroadbandAll carbons as singlets

  • 13C NMR 6-methyl-5-hepten-2-ol DEPT 90Only CH carbons

  • 13C NMR 6-methyl-5-hepten-2-olDEPT 135Methyl and CH positiveMethylene negative

  • ENDC13 NMR

    C environment , ppmC environment , ppm

    Saturated carbons 0-55Acetylenic

    -

    C C

    -

    60-90

    primary

    R-

    C

    H

    3

    4-30

    secondary

    R

    2

    -

    C

    H

    2

    12-50Benzenoid 120-140

    tertiary

    R

    3

    -

    C

    H

    22-54

    quaternary

    R

    4

    -

    C

    29-47Carbonyl

    C

    =O

    150-220

    amides & imides150-180

    Olefinic carbons 100-165 esters & anhydrides155-185

    R

    2

    C=

    C

    H

    2

    100-110 acids170-190

    R-CH=

    C

    H

    2

    110-120 ketones185-220

    R-CH=

    C

    H-R

    125-150 aldehydes190-210

    CH

    2

    =

    C

    H-R

    130-154

    CH

    2

    =

    C

    R

    2

    140-165Nitriles

    R-

    C

    N

    115-125

    Alenes Azomethine

    R

    2

    C

    =N-R

    145-165

    C

    =C=

    C

    70-95

    C=

    C

    =C

    200-215