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Interpreting the
Carbon-13 13C NMR spectrum of cyclohexene
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Brown's Chemistry Advanced Level Pre-University Chemistry Revision Study
Notes for UK IB KS5 A/AS GCE advanced A level organic chemistry students US
K12 grade 11 grade 12 organic chemistry courses involving molecular
spectroscopy analysing C-13 NMR spectra of cyclohexene
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C-13
NMR spectroscopy - spectra index
TMS is the acronym for tetramethylsilane, formula Si(CH3)4,
whose 13C atoms are arbitrarily given a chemical shift of 0.0
ppm. This is the 'standard' in 13C NMR spectroscopy and all other
13C resonances, called chemical shifts, are measured with
respect to the TMS, and depend on the
individual (electronic) chemical environment of the 13C atoms in
an organic molecule - cyclohexene here.
cyclohexene
,
 ,
,
Interpreting the C-13 NMR spectrum of cyclohexene
As you can see from the diagram above there are
3 different chemical shift lines in the C-13 NMR spectrum of
cyclohexene
indicating 3 different chemical environments of the 10 carbon
atoms of cyclohexene.
13C chemical shifts δ (a) to (c) on the C-13 NMR
spectrum diagram for cyclohexene.
(a) structure : 13C NMR chemical shift
δ of 22.8 ppm
The 13C NMR resonance for the 2 x
equivalent
C atoms furthest from the C=C bond.
(b) structure : 13C NMR
chemical shift δ of 25.3 ppm
The 13C NMR resonance for the 2 x
equivalent
C atoms nearest to the C=C bond.
(c) structure : 13C NMR
chemical shift δ of 127.3 ppm
The 13C NMR resonance for the 2 x
equivalent C atoms of
the actual C=C bond itself.
The presence of the pi electron cloud
produces the largest chemical shift for the C=C bond carbons
compared to the other two.
The carbon-13 NMR spectra provides direct evidence of
3 different carbon atom environments for the 10 carbon atoms in the
cyclohexene molecule,
deduced from the presence of 3 different 13C NMR chemical
shifts (ppm).
Key words & phrases:
isomer of molecular C6H10
formula Interpreting the C-13 NMR spectra of
cyclohexene, 13C nmr spectrum of cyclohexene, understanding the carbon-13 nmr spectrum of
cyclohexene,
explaining the line pattern in the high resolution C-13 nmr spectra of
cyclohexene,
revising the C-13 nmr spectrum of cyclohexene, ppm chemical shifts of the C-13 nmr
spectrum of cyclohexene, how to construct the diagram of the C-13 nmr spectrum of
cyclohexene,
how to analyse the chemical shifts in the carbon-13 NMR spectrum of cyclohexene deducing
the chemical environment of all the carbon atoms in cyclohexene examining the c13 nmr
spectrum of cyclohexene analysing the 13C nmr spectrum of cyclohexene how do you sketch and interpret the C-13 NMR spectrum
of cyclohexene interpreting interpretation of the C-13 NMR spectrum of
cyclohexene
assignment of chemical shifts in the 13C
NMR spectrum of cyclohexene alkene functional group
Links associated
with cyclohexene
The infrared spectrum of cyclohexene
The mass
spectrum of cyclohexene
The H-1
NMR spectrum of cyclohexene
The chemistry of ALKENES
revision notes INDEX
C-13
NMR spectroscopy index
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