Chapter 18, Problem 48PP

Interpretation Introduction

Interpretation: For the given compounds, number of signals in ${}^{\text{13}}\text{C}\text{NMR}$ spectrum should be found

Concept introduction:

• The carbon atoms of aromatic rings typically produce signals in the range of 100-150ppm in ${}^{\text{13}}\text{C NMR}$ spectrum. The number of signals is very helpful in determining the specific substitution for substituted aromatic ring.
• The ${}^{\text{13}}\text{C}\text{NMR}$ spectrum gives information on the different electronic environments of carbon. As like ${}^{\text{1}}\text{H}\text{NMR}$, the number of signals generated in ${}^{\text{13}}\text{C}\text{NMR}$ are predicted by performing symmetry operations (rotation or reflection symmetry). Only chemical shift values are reported in the spectrum but not the multiplicity and integration values because the coupling between two neighboring ${}^{\text{13}}\text{C}{-}^{\text{13}}\text{C}$ nuclei are weakly involved due to the low abundance of ${}^{\text{13}}\text{C}$ isotopes of carbon atom.