Figure 2: HCCOSW spectrum of 2-nitroaniline in CDCl3, including a comparison of predicted 13C
shifts for carbons 4 and 6. The value calculated by Gaussian correlates to the experimental
observation that the carbon 4 shift will be less than the carbon 6 shift while an additive
calculation and the chemdraw prediction indicate the opposite order.
Figure 3: O-anisaldehyde in CDCl3 with TMS 13C NMR. Peak assignments were made based on
calculated values and expected shifts. The C-6 and C-4 peaks were far enough apart that it was
unlikely they would be switched.
Figure 4: The 1H NMR of 2-nitroaniline in CDCl3.
Figure 5: Carbon 13 spectra of 2-nitroaniline in CDCl3. Carbons 4 and 6 show up, in some order,
and 117.36 ad 119.15ppm. The definitive peak assignments were determined from the 2D
Figure 6: HCCOSW of o-anisidine, indicating that the assignments of C-4 and C-6 are as expected
Figure 7: Proton NMR of o-anisidine run with a smaller concentration than previous scans to
improve resolution. The peaks of interest, hower, are still not clear. The four peaks needed to
definitively assign carbons shifts using a 2D spectrum are within 0.1 ppm of one another and
Figure 8: A comparison of 13C shifts of o-anisidine on the 13C NMR of o-anisidine in CDCl3. It was
noted that the Chemdraw predictions, additive values, and Japanese database values were
similar to the experimentally observed shifts. The Gaussian calculations were significantly
different. It was determined that the Gaussian calculations were off because the structure used
to calculate them was an incorrect conformation of the molecule.
Figure 9: HCCOSW of 2-methoxybenzonitrile. Carbons 4 and 6 have similar shifts (134.83 and
134.13ppm). The corresponding proton peaks are overlapping, consisting of a triplet and a
doublet. Since they are overlapping, the carbon peaks cannot be definitively assigned.
Figure 10: Carbon-13 spectrum of 2-methoxybenzonitrile in CDCl3. Peaks were assigned except
for carbons 4 and 6, are at 134.83 and 134.13ppm.
Figure 11: Proton spectra of 2-methoxybenzonitrile in CDCl3. The peaks of interest (from the
protons on carbons 4 and 6) are overlapping and the order cannot be clearly discerned.
Figure 12: HCCOSW spectrum of 2-methoxybenzaldehyde (o-anisaldehyde). While an order of
the triplet and doublet around 7ppm was assigned, it is not clearly distinguishable and thus an
absolute peak assignment could not be made based on this data. However, the 13C peaks were
at the expected shifts so they are believed to be where they belong.
Figure 13: Proton spectrum of o-anisaldehyde (2-methyoxybenzaldehyde) in CDCl3 with TMS.
The peaks of interest occur at 6.95-7.05ppm and include a doublet and a triplet. Since the peaks
are overlapping, the actual order in which they occur is not known.
C6 and C4 Shielding
Compound X Y Gaussian SDBS
guaiacol y y 13.8846 10.6
o-anisidine y amine 13.8846 10.58
methoxytolu hox methyl
ene y group 11.7926 10.36
2- hox ethan
ethylanisole y e 12.1953 10.26
methoxyphe met carbox
nylacetic hox ylic
acid y acid 10.5314 10
zonitrile y nitrile 10.7644 9.34
o- hox chlorin
chloroanisole y e 10.904 9.09
o- hox nitro
nitroanisole y group 7.3634 8.89
methoxyben hox aldehy
zaldehyde y de 11.431 8.83
methoxyacet hox ethan
ophenone y one 10.7407 8.77
2-nitroaniline ne group -1.2491 2.14
benzene H H 0 0
Table 1: Calculated difference between 13C CPD shift for C6 and C4 based on rules of additivity
(data provided from SDBS database) and Gaussian O3LYP calculations. Since only three
compounds were tested the experimental results were not posted in this table.