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Shifting of axial and equatorial protons
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Adrian Lee
Shifting of axial and equatorial protons
The distinction between axis and equatorial hydrogens is not going to be visible in an NMR spectrum for cyclohexanol. The conformations of the molecule interconvert too quickly at room temperature to make a distinction in the proton NMR spectrum.
So, in practice, you will only see 4 distinct C-H bond types in the molecule and the splits that will be visible on your spectrum depend on the resolution (which is not particularly high on the spectrum you have). The splits cause by neighbouring hydrogens for the groups between shifts of 1 and 2 overlap even in high resolution spectra and it isn't clear whether what you are seeing this jumble of peaks as 4 separate environments because of the low resolution or whether one of the peaks is an impurity.
Some software packages for structure drawing also generate theoretical NMR plots which can help interpret such spectra.
The distinction between axis and equatorial hydrogens is not going to be visible in an NMR spectrum for cyclohexanol. The conformations of the molecule interconvert too quickly at room temperature to make a distinction in the proton NMR spectrum.
So, in practice, you will only see 4 distinct C-H bond types in the molecule and the splits that will be visible on your spectrum depend on the resolution (which is not particularly high on the spectrum you have). The splits cause by neighbouring hydrogens for the groups between shifts of 1 and 2 overlap even in high resolution spectra and it isn't clear whether what you are seeing this jumble of peaks as 4 separate environments because of the low resolution or whether one of the peaks is an impurity.
Some software packages for structure drawing also generate theoretical NMR plots which can help interpret such spectra.
‘The distinction between axial and equatorial hydrogens is not going to be visible in an NMR spectrum for cyclohexanol’ — it’s right there in OP’s spectrum. If you deem that spectrum incorrect, I demand you show corresponding 2D spectra that More
Here is a high resolution spectra for cyclohexanol which has a deuterium in the OH group. More
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The 4 conformations (2 chair & 2 boat) of the molecule interconvert too quickly at room temperature to make a distinction in the shown proton NMR spectrum.
From SDBS.
(1) Enter Cyclohexanol
(2) Select full math & H NMR
(3) Search
(4) Select 1H NMR : 400 MHz in CDCl3 on left side
One of the possible 4 conformations of the molecule is shown below.
Assign......#.....Shift(ppm)
A 1 3.578
B 1 2.84
C 2 1.882
D 2 1.728
E 1 1.542
F 4 1.30 to 1.22
G 1 1.16
So the OP was wrong that the 3 peaks at 1.9, 1.7,1.5 all represent equatorial protons. There are 2-2-1 protons at those peaks.
The 4 conformations (2 chair & 2 boat) of the molecule interconvert too quickly at room temperature to make a distinction in the shown proton NMR spectrum.
From SDBS.
(1) Enter Cyclohexanol
(2) Select full math & H NMR
(3) Search
(4) Select 1H NMR : 400 MHz in CDCl3 on left side
One of the possible 4 conformations of the molecule is shown below.
Assign......#.....Shift(ppm)
A 1 3.578 B 1 2.84 C 2 1.882 D 2 1.728 E 1 1.542 F 4 1.30 to 1.22 G 1 1.16
So the OP was wrong that the 3 peaks at 1.9, 1.7,1.5 all represent equatorial protons. There are 2-2-1 protons at those peaks.
The distinction between axis and equatorial hydrogens is not going to be visible in an NMR spectrum for cyclohexanol. The conformations of the molecule interconvert too quickly at room temperature to make a distinction in the proton NMR spectrum.
So, in practice, you will only see 4 distinct C-H bond types in the molecule and the splits that will be visible on your spectrum depend on the resolution (which is not particularly high on the spectrum you have). The splits cause by neighbouring hydrogens for the groups between shifts of 1 and 2 overlap even in high resolution spectra and it isn't clear whether what you are seeing this jumble of peaks as 4 separate environments because of the low resolution or whether one of the peaks is an impurity.
Some software packages for structure drawing also generate theoretical NMR plots which can help interpret such spectra.
The distinction between axis and equatorial hydrogens is not going to be visible in an NMR spectrum for cyclohexanol. The conformations of the molecule interconvert too quickly at room temperature to make a distinction in the proton NMR spectrum.
So, in practice, you will only see 4 distinct C-H bond types in the molecule and the splits that will be visible on your spectrum depend on the resolution (which is not particularly high on the spectrum you have). The splits cause by neighbouring hydrogens for the groups between shifts of 1 and 2 overlap even in high resolution spectra and it isn't clear whether what you are seeing this jumble of peaks as 4 separate environments because of the low resolution or whether one of the peaks is an impurity.
Some software packages for structure drawing also generate theoretical NMR plots which can help interpret such spectra.
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The 4 conformations (2 chair & 2 boat) of the molecule interconvert too quickly at room temperature to make a distinction in the shown proton NMR spectrum.
From SDBS.
(1) Enter Cyclohexanol
(2) Select full math & H NMR
(3) Search
(4) Select 1H NMR : 400 MHz in CDCl3 on left side
One of the possible 4 conformations of the molecule is shown below.
So the OP was wrong that the 3 peaks at 1.9, 1.7,1.5 all represent equatorial protons. There are 2-2-1 protons at those peaks.
The 4 conformations (2 chair & 2 boat) of the molecule interconvert too quickly at room temperature to make a distinction in the shown proton NMR spectrum.
From SDBS.
(1) Enter Cyclohexanol
(2) Select full math & H NMR
(3) Search
(4) Select 1H NMR : 400 MHz in CDCl3 on left side
One of the possible 4 conformations of the molecule is shown below.
So the OP was wrong that the 3 peaks at 1.9, 1.7,1.5 all represent equatorial protons. There are 2-2-1 protons at those peaks.
More
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