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Advanced Organic Chemistry: 1H NMR spectrum of 1,1-dichloroethane

Interpreting the H-1 hydrogen-1 (proton) NMR spectrum of 1,1-dichloroethane

Doc 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 H-1 NMR spectra of 1,1-dichloroethane

1H proton nmr spectrum of 1,1-dichloroethane low/high resolution diagrams C2H4Cl2 CH3CHCl2 analysis interpretation of chemical shifts ppm spin spin line splitting diagram H1 H-1 nmr for 1,1-dichloroethane explaining spin-spin coupling for line splitting doc brown's advanced organic chemistry revision notes

TMS is the acronym for tetramethylsilane, formula Si(CH3)4, whose protons are arbitrarily given a chemical shift of 0.0 ppm. This is the 'standard' in 1H NMR spectroscopy and all other proton resonances, called chemical shifts, are measured with respect to the TMS, and depend on the individual (electronic) chemical environment of the hydrogen atoms in an organic molecule - 1,1-dichloroethane here.

The chemical shifts quoted in ppm on the diagram of the H-1 NMR spectrum of 1,1-dichloroethane represent the peaks of the intensity of the chemical shifts of (which are often groups of split lines at high resolution) AND the relative integrated areas under the peaks gives you the ratio of protons in the different chemical environments of the 1,1-dichloroethane molecule.

1,1-dichloroethane,  C2H4Cl2,  CH3-CHCl2

Interpreting the H-1 NMR spectrum of 1,1-dichloroethane

In terms of spin-spin coupling from the possible proton magnetic orientations, for 1,1-dichloroethane I have only considered the interactions of non-equivalent protons on adjacent carbon atoms e.g. -CH-CH3.

For relatively simple molecules, the low resolution H-1 NMR spectrum of 1,1-dichloroethane is a good starting point (low resolution diagram above).

The hydrogen atoms (protons) of 1,1-dichloroethane occupy 2 different chemical environments so that the low resolution NMR spectra should show 2 principal peaks of different H-1 NMR chemical shifts in the ratio 3:1. (diagram above for 1,1-dichloroethane).

CH3-CHCl2

Note the proton ratio 3:1 of the 2 colours of the protons in the 2 chemically different proton environments

Chemical shifts (a) to (b) on the H-1 NMR spectrum diagram for 1,1-dichloroethane.

Although there are 4 hydrogen atoms in the molecule, there are only 2 possible different chemical environments for the hydrogen atoms in 1,1-dichloroethane molecule.

The integrated signal proton ratio 3:1 observed in the high resolution H-1 NMR spectrum, corresponds with the structural formula of 1,1-dichloroethane.

The high resolution 1H NMR spectrum of 1,1-dichloroethane

The high resolution spectra of 1,1-dichloroethane shows 2 groups of proton resonances and in the 3:1 ratio expected from the structural formula of 1,1-dichloroethane.

The ppm quoted on the diagram represent the peak of resonance intensity for a particular proton group in the molecule of 1,1-dichloroethane - since the peak' is at the apex of a band of H-1 NMR resonances due to spin - spin coupling field splitting effects - see high resolution notes on 1,1-dichloroethane below.

So, using the chemical shifts and applying the n+1 rule to 1,1-dichloroethane and make some predictions using some colour coding! (In problem solving you work the other way round!)

(a) 1H Chemical shift 5.90 ppm for the CH proton: CH3-CHCl2

The CH proton resonance is split into a 1:3:3:1 quartet by the methyl protons (n+1 = 4).

Evidence for the presence of a CH3 group in the molecule of 1,1-dichloroethane

(b) 1H Chemical shift 2.06 ppm for the methyl protons: CH3-CHCl2

The CH3 proton resonance is split into a 1:1 doublet by the CH proton (n+1 = 2).

Evidence for the presence of a CH group in the molecule of 1,1-dichloroethane


Number of directly adjacent protons 1H causing splitting Splitting pattern produced from the n+1 rule on spin-spin coupling and the theoretical ratio of line intensities
0 means no splitting             1            
1 creates a doublet           1   1          
2 creates a triplet         1   2   1        
3 creates a quartet       1   3   3   1      
4 creates a quintet     1   4   6   4   1    
5 creates a sextet   1   5   10   10   5   1  
6 creates a septet 1   6   15   20   15   6   1

Key words & phrases: C2H4Cl2 CH3CHCl2 Cl2CHCH3 CHCl2CH3 Interpreting the proton H-1 NMR spectra of 1,1-dichloroethane, low resolution & high resolution proton nmr spectra of 1,1-dichloroethane, H-1 nmr spectrum of 1,1-dichloroethane, understanding the hydrogen-1 nmr spectrum of 1,1-dichloroethane, explaining the line splitting patterns from spin-spin coupling  in the high resolution H-1 nmr spectra of 1,1-dichloroethane, revising the H-1 nmr spectrum of 1,1-dichloroethane, proton nmr of 1,1-dichloroethane, ppm chemical shifts of the H-1 nmr spectrum of 1,1-dichloroethane, explaining and analyzing spin spin line splitting in the H-1 nmr spectrum, how to construct the diagram of the H-1 nmr spectrum of 1,1-dichloroethane, how to work out the number of chemically different protons in the structure of the 1,1-dichloroethane organic molecule, how to analyse the chemical shifts in the hydrogen-1 H-1 proton NMR spectrum of 1,1-dichloroethane using the n+1 rule to explain the spin - spin coupling ine splitting in the proton nmr spectrum of 1,1-dichloroethane deducing the nature of the protons from the chemical shifts ppm in the H-1 nmr spectrum of 1,1-dichloroethane examining the 1H nmr spectrum of  1,1-dichloroethane analysing the 1-H nmr spectrum of 1,1-dichloroethane how do you sketch and interpret the H-1 NMR spectrum of 1,1-dichloroethane interpreting interpretation of the 1H proton spin-spin coupling causing line splitting in the NMR spectrum of 1,1-dichloroethane  assignment of chemical shifts in the proton 1H NMR spectrum of 1,1-dichloroethane formula explaining spin-spin coupling for line splitting for 1,1-dichloroethane halide chloride chloro functional group


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