1H-NMR spectra interpretation Examples , Tables and Problems

Nuclear Magnetic Resonance 1H-nmr spectrum: Chemical Shift

How 1H NMR spectrum for p-xylene will appear? How many H type are their? This will inform us the number of signals in the spectra How many H atoms in each type? This will inform us the area of each signal What are the functional groups near each H type? This will inform us where the signal will appear (chemical shift d) How many H atoms are attached to the carbon atom s nearby each H type? This will inform us how the splitting pattern will appear for each signal

How 1H NMR spectra for p-xylene will appear? b a 6H at about 2.2 ppm singlet b 4H at about 7.0 ppm singlet

How 1H NMR spectra for tert-butyl bromide will appear? a singlet 9H at about 1.8ppm

How 1H NMR spectra for ethyl bromide will appear? a b CH3CH2-Br a triplet 3H b quartet 2H ethyl bromide

Draw the chemical structure for the compound Number of signals in the spectra  will inform us the number of H type in the molecule Area of each signal  will inform us the number of H atoms in each type Chemical shift d of the signal  will inform us about closeness of H type to the functional group Splitting pattern for each signal  will inform us how many H atoms surrounding each type

Draw the chemical structure for the compound C3H7Br a triplet 3H b complex 2H c triplet 2H c b a

Draw the chemical structure for the compound C3H7Br C3H7Br has IHD = 0  no unsaturation (no double bonds nor cycles), so it is chain molecule (straight or branched). From the given data, there are three signals (a, b and c) so there are three types of H atoms, each type will be at a unique carbon atom. It is obvious that there is no symmetry in the molecule, the formula has 7H atoms and they are distributed on three separate signals (3+2+2). We have CH3-, -CH2- and -CH2- c signal has the higher d value (more deshielded atoms), this mean that this H type of atoms are the nearest to the Br atom. We could use tables to check for this, so c signal should be like this -CH2-Br The splitting pattern shows that a signal is triplet, this mean that it has only 2H atoms surrounding it, so this side of the molecule will be CH3-CH2- because it has only one side to attach with. Now, the final touch, the like between the tow ends, it is the b hydrogens. This will form CH3-CH2-CH2-Br. This justify the splitting patterns for b and c. a b c c a a b c

Draw the chemical structure for the compound C3H7Br 1-bromopropane a b c CH3CH2CH2-Br a triplet 3H b complex 2H c triplet 3H

Try the same methodology for C3H7Cl spectra below a doublet 6H b septet 1H b a Answer: isopropyl chloride

Draw the chemical structure for the compound C4H9Br a triplet 3H b doublet 3H c complex 2H d sextet 1H

Draw the chemical structure for the compound C8H9Cl

Draw the chemical structure for the compound C2H6O a triplet 3H b singlet 1H c quartet 2H

Draw the chemical structure for the compound C8H10 a triplet 3H b quartet 2H c ~singlet 5H

Draw the chemical structure for the compound C6H14O a triplet 6H b complex 4H c triplet 4H

Draw the chemical structure for the compound C10H14

Draw the chemical structure for the compound C5H11Br a triplet 3H b singlet 6H c quartet 2H b & c overlap

Draw the chemical structure for the compound C3H8O a triplet 3H b complex 2H c singlet 1H d triplet 2H

Draw the chemical structure for the compound C11H16 a 9H = 3CH3, no neighbors c 5H = monosubstituted benzene b 2H, no neighbors 9H 2H 5H

Draw the chemical structure for the compound C4H8Br2 a = 6H, two CH3 with no neighbors (CH3)2C— b = CH2, no neighbors & shifted downfield due to Br 2H

C7H8O c = monosubst. benzene b = CH2 c = OH 5H 2H 1H