Advanced Organic Chemistry: H-1 NMR spectrum of cyclopropane

SITEMAP * HOME PAGE * SEARCH * GCSE Level Chemistry age ~14-16 * Advanced Level Chemistry age ~16-19

The H-1 hydrogen-1 (proton) NMR spectrum of cyclopropane

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 cyclopropane

email doc brown

Use your mobile phone or ipad etc. in 'landscape' mode

This is a BIG website, you need to take time to explore it

H-1 proton NMR spectroscopy - spectra index

See also comparing the infrared, mass, 1H NMR and 13C NMR spectra of propane, cyclopropane and propene

low and high resolution H-1 proton nmr spectrum of cyclopropane analysis interpretation of chemical shifts ppm spin spin line splitting diagram H1 1-H nmr for cyclopropane 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 shifts, called chemical shifts, depend on the individual (electronic) chemical environment of the hydrogen atoms in an organic molecule - cyclopropane here.

The chemical shifts quoted in ppm on the diagram of the H-1 NMR spectrum of cyclopropane 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 cyclopropane molecule.

Cyclopropane C3H6, alkanes structure and naming (c) doc b , alkanes structure and naming (c) doc b

Interpreting the H-1 NMR spectrum of cyclopropane

All eight hydrogen atoms are equivalent as cyclopropane is a highly symmetrical molecule, the three carbon atoms are in the same plane with the protons distributed symmetrically above and below the plane of the triangle of carbon atoms.

Therefore only one 1H Chemical shift of 0.20 ppm is observed and with no splitting - there are no neighbouring non-equivalent protons.

The presence of one unsplit proton NMR resonance shows that all 6 protons occupy the same chemical environment.


Number of protons 1H causing splitting Splitting pattern produced from the n+1 rule 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
Comparing the infrared, mass, 1H NMR and 13C NMR spectra of propane, cyclopropane and propene

NOTE: The images are linked to their original detailed spectral analysis pages AND can be doubled in size with touch screens to increase the definition to the original ethane and ethene image sizes.

Comparing the infrared spectra of propane, propene and cyclopropane.

Cyclopropane and propene are structural isomers of molecular formula C3H6.

Propane and propene exemplify the infrared spectra of lower members of  the alkane and alkene homologous series of CnH2n+2 and CnH2n hydrocarbon molecules where n = 3.

INFRARED SPECTRA (above): Apart from the significant differences in the fingerprint region at wavenumbers 1500 to 400 cm-1, the most striking differences are: (i) propene shows the characteristic absorption at ~1700 cm-1 for the C=C stretching vibrations, absent in the other two spectra, (ii) cyclopropane shows an absorption band at 2200 cm-1, absent in the other two spectra, (iii) propane has an absorption band at ~750 cm-1, absent in the other two spectra.

Comparing the mass spectra of propane, propene and cyclopropane.

Cyclopropane and propene are structural isomers of molecular formula C3H6.

Propane and propene exemplify the mass spectra of lower members of  the alkane and alkene homologous series of CnH2n+2 and CnH2n hydrocarbon molecules where n = 3.

MASS SPECTRA (above): All three hydrocarbons show some similarities in their mass spectra e.g. m/z ions 26 to 28 for [C2Hx]+ (x = 2 to 4) and m/z 14 and 15 ions - but these are found in most aliphatic hydrocarbon spectra. The molecular ion peaks will be the same for the isomeric propene and cyclopropane (m/z 42) but that of propane will be 2 mass units higher at m/z 44. The base ion peak m/z values are all different, propane 29, propene 41 and cyclopropane 42.

Comparing the 1H proton NMR spectra of propane, propene and cyclopropane.

Cyclopropane and propene are structural isomers of molecular formula C3H6.

Propane and propene exemplify the 1H proton NMR spectra of lower members of  the alkane and alkene homologous series of CnH2n+2 and CnH2n hydrocarbon molecules where n = 3.

1H NMR SPECTRA (above): The 1H NMR spectra of all three molecules give different proton ratios i.e. propane 3:1 (actually 6:2 in the molecule), propene 2:1:3 (spectrum and molecule) and cyclopropane just a singlet for the six protons, so all three can be distinguished from each other by their 1H NMR spectra..

Comparing the carbon-13 NMR spectra of propane, propene and cyclopropane.

Cyclopropane and propene are structural isomers of molecular formula C3H6.

Propane and propene exemplify the carbon-13 NMR spectra of lower members of  the alkane and alkene homologous series of CnH2n+2 and CnH2n hydrocarbon molecules where n = 3.

13C NMR SPECTRA (above): The 13C NMR spectra of the three molecules show different numbers of carbon-13 chemical environments i.e propane 2, propene 3 and cyclopropane only 1, so all three could be distinguished from each other.

Key words & phrases: Interpreting the proton H-1 NMR spectra of cyclopropane, low resolution & high resolution proton nmr spectra of cyclopropane, H-1 nmr spectrum of cyclopropane, understanding the hydrogen-1 nmr spectrum of cyclopropane, explaining the line splitting patterns in the high resolution H-1 nmr spectra of cyclopropane, revising the H-1 nmr spectrum of cyclopropane, proton nmr of cyclopropane, ppm chemical shifts of the H-1 nmr spectrum of cyclopropane, 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 cyclopropane, how to work out the number of chemically different protons in the structure of the cyclopropane organic molecule, how to analyse the chemical shifts in the hydrogen-1 H-1 proton NMR spectrum of cyclopropane using the n+1 rule to explain the spin - spin coupling ine splitting in the proton nmr spectrum of cyclopropane deducing the nature of the protons from the chemical shifts ppm in the H-1 nmr spectrum of cyclopropane examining the 1H nmr spectrum of  cyclopropane analysing the 1-H nmr spectrum of cyclopropane how do you sketch and interpret the H-1 NMR spectrum of cyclopropane interpreting interpretation of the H-1 proton NMR spectrum of cyclopropane Molecular structure diagram of the proton NMR diagram for the 1H NMR spectrum of cyclopropane. The proton ratio in the 1H NMR spectrum of cyclopropane. Deducing the number of different chemical environments of the protons in the cyclopropane molecule from the 1H chemical shifts in the hydrogen-1 NMR spectrum of cyclopropane. Analysing the high resolution 1H NMR spectrum of cyclopropane. Analysing the low resolution 1H NMR spectrum of cyclopropane. You may need to know the relative molecular mass of cyclopropane to deduce the molecular formula from the proton ratio of the 1H NMR spectrum of cyclopropane. Revision notes on the proton NMR spectrum of cyclopropane. Matching and deducing the structure of the cyclopropane molecule from its hydrogen-1 NMR spectrum.


Links associated with cyclopropane

The chemistry of ALKANES revision notes INDEX

The infrared spectrum of cyclopropane

The mass spectrum of cyclopropane

The C-13 NMR spectrum of cyclopropane

H-1 proton NMR spectroscopy index  (Please read 8 points at the top of the 1H NMR index page)

ALL SPECTROSCOPY INDEXES

All Advanced Organic Chemistry Notes

Use My Google search site box

Email doc b: chem55555@hotmail.com

TOP OF PAGE