
Chapter 15, Problem 40PP
Interpretation: The structure of a given molecular formula
C8H18
to be predicted using
1H NMR
and
13C NMR
spectra.
Concept Introduction:
The
13C NMR
spectrum gives information on the different electronic environments of carbon. As like
1H NMR
, the number of signals generated in
13C 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
13C−13C
nuclei are weakly involved due to the low abundance of
13C
isotopes of carbon atom.
HDI Calculation:
HDI=2(C)+2+N-H-X2whereC represent the number of carbonN represent the number of nitrogenH represent the number of hydrogenX represent the number of halogen.