Advanced Organic Chemistry: 1H NMR spectrum E-pent-2-ene and Z-pent-2-ene CH3CH=CHCH2CH3

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

Interpreting the H-1 hydrogen-1 (proton) NMR spectrum of E-pent-2-ene and Z-pent-2-ene (E/Z geometrical isomers)

[Author © Dr Phil Brown PhD: Doc Brown's advanced level organic chemistry exam revision notes suitable for students of UK A level chemistry courses & US K12 grade 11, grade 12 and AP honors chemistry courses: Molecular spectroscopy analysis of E/Z isomers of pent-2-ene [spectra page updated Mar 25th 2026 *]

 email doc brown  Re-edit 1H NMR spectrum of CH3CH2CH=CHCH3

This is a BIG chemistry website, PLEASE take time to explore it

Links associated with E-pent-2-ene and Z-pent-2-ene

H-1 proton NMR spectroscopy - spectra index  *  [privacy policy, cookies and disclaimer]

Introductory note on the 1H NMR spectra of E/Z pent-2-ene (cis/trans isomers)

Students and teachers please note my explanation of the proton NMR spectrum of E/Z pent-2-ene (cis/trans isomers) is designed for advanced, but pre-university, chemistry courses.

The chemical shift δ splitting pattern effects for E/Z pent-2-ene (cis/trans isomers) are confined to a proton spin-spin coupling effects analysed using the n+1 rule for adjacent non-equivalent proton fields (n is the number of neighbouring protons in a non-equivalent different chemical environment for the E/Z pent-2-ene (cis/trans isomers) molecule).

It is assumed that the integrated intensities of the 1H NMR δ chemical shifts give the ratio of the protons in the different non-equivalent chemical environments of the E/Z pent-2-ene (cis/trans isomers) molecule.

The most common solvent used for investigating the 1H NMR spectrum of compounds like E/Z pent-2-ene (cis/trans isomers), is CDCl3 and other deuterated solvents to avoid confusion with a 1H NMR signal, 2D (2H) has a different NMR chemical shift.

C5H10 low and high resolution H-1 proton nmr spectrum of E-pent-2-ene 2-pentene analysis interpretation of chemical shifts ppm spin spin line splitting diagram H1 1-H nmr for trans-pent-2-ene doc brown's advanced organic chemistry revision notes

The H-1 proton NMR spectrum of the stereoisomer E-pent-2-ene (trans-2-pentene)

 

C5H10 low and high resolution H-1 proton nmr spectrum of 2-pentene Z-pent-2-ene analysis interpretation of chemical shifts ppm spin spin line splitting diagram H1 1-H nmr for cis-pent-2-ene doc brown's advanced organic chemistry revision notes

The H-1 proton NMR spectrum of the stereoisomer Z-pent-2-ene (cis-2-pentene)

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 - E-pent-2-ene and Z-pent-2-ene here.

The chemical shifts quoted in ppm on the diagram of the H-1 NMR spectrum of E-pent-2-ene and Z-pent-2-ene 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 E-pent-2-ene and Z-pent-2-ene molecule.

Pent-2-ene C5H10, alkenes structure and naming (c) doc b has two E/Z isomers E-pent-2-ene and Z-pent-2-ene

Z/cis- alkenes structure and naming (c) doc b , E/trans- alkenes structure and naming (c) doc b

The molecular structure and naming of alkenes

Interpreting the H-1 NMR spectrum of E-pent-2-ene and Z-pent-2-ene

For relatively simple molecules, the low resolution H-1 NMR spectrum of E-pent-2-ene and Z-pent-2-ene is a good starting point (low resolution diagram above), but two of the resonances (CH=CH protons) are close together and would show up as a ratio number of (2) compared to CH2 (2) and 2 x CH3 (2 x 3).

The hydrogen atoms (protons) of E-pent-2-ene and Z-pent-2-ene occupy 5 different chemical environments so that the low resolution NMR spectra should show five 1H peaks of different H-1 NMR chemical shifts (diagram above for E-pent-2-ene and Z-pent-2-ene).

CH3CH=CHCH2CH3

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

Although there are 10 hydrogen atoms in the molecule, there are only 5 possible different chemical environments for the hydrogen atoms in E-pent-2-ene and Z-pent-2-ene molecule.

The integrated signal proton ratio ? observed, corresponds with the structural formula of E-pent-2-ene and Z-pent-2-ene.

The high resolution H-1 NMR spectrum of E-pent-2-ene and Z-pent-2-ene

At very high resolution, the H-1 NMR spectra of E-pent-2-ene and Z-pent-2-ene show 5 groups of proton resonances and in the 3:1:1:2:3 ratio expected from the formula of pent-2-ene.

The ppm quoted on the diagram represent the peak of resonance intensity for a particular proton group in the molecule of E-pent-2-ene and Z-pent-2-ene - 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 E-pent-2-ene and Z-pent-2-ene below.

So, using the chemical shifts and applying the n+1 rule to E-pent-2-ene and Z-pent-2-ene and make some predictions using some colour coding! (In problem solving you work the other way round!)

The H-1 NMR spectra for the E/Z stereoisomers of pent-2-ene are quite similar, with only small differences in the 1H chemical shifts for each group of protons (a) to (e).

Both proton NMR spectra are quite similar, the protons attached to the >C=C< double bond both have a larger 1H chemical shifts close together, whereas the other protons of the linear alkyl group have similar and lower shifts, also relatively close together.

Although not identical spectra, both pent-2-ene E/Z isomers show a very similar pattern of 1H NMR chemical shifts.

(a) 1H Chemical shift for the CH3 protons CH3CH=CHCH2CH3

1.64 ppm (E) and 1.60 ppm (Z):

Both resonances split into a 1:1 doublet by the 'purple' CH proton (n+1 = 2).

Evidence for the presence of a CH group in the molecule of E-pent-2-ene and Z-pent-2-ene

(b) 1H Chemical shift for the CH proton CH3CH=CHCH2CH3

5.40 ppm (E) and 5.40 ppm (Z):

Both resonances split into a 1:4:6:4:1 quintet by the 'blue' CH3 and 'green' CH protons (n+1 = 5)

Evidence for the presence of a CH3-CH-CH group in the molecule of E-pent-2-ene and Z-pent-2-ene (but can get a quintet from CH2-CH-CH2 grouping too).

(c) 1H Chemical shift for the CH proton CH3CH=CHCH2CH3

5.47 ppm (E) and 5.38 ppm (Z):

Both resonances split into a 1:3:3:1 quartet by the 'purple' CH proton and the 'brown' CH2 protons (n+1 = 4).

(b) and (c) resonances are very close together and need a very high resolution spectra of E/Z pent-2-ene to sort them out.

(d) 1H Chemical shift for the CH2 protons CH3CH=CHCH2CH3

1.97 ppm (E) and 2.04 ppm (Z):

Both resonances split into a 1:4:6:4:1 quintet by the 'red' CH3 and 'green' CH protons (n+1 = 5)

Evidence for the presence of a CHCH2CH3 group in the molecule of E-pent-2-ene and Z-pent-2-ene (but can get a quintet from CH2-CH-CH2 grouping too).

(e) 1H Chemical shift for the CH3 protons CH3CH=CHCH2CH3

0.96 ppm (E) and 0.96 ppm (Z):

Both resonances split into a 1:2:1 triplet by the 'brown' CH2 protons (n+2 = 3)

Evidence for the presence of a CH2 group in the molecule of E-pent-2-ene and Z-pent-2-ene

The 1H NMR chemical shifts tend to much higher for protons directly bonded to the carbon atoms of the C=C double bond compared to those not so.

The splitting pattern from proton spin-spin coupling effects is analysed using the n+1 rule for adjacent non-equivalent proton fields (n is the number of neighbouring protons in a non-equivalent different chemical environment).

Number of directly adjacent 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

Key words & phrases: C5H10 Interpreting the proton H-1 NMR spectra of E-pent-2-ene and Z-pent-2-ene, low resolution & high resolution proton nmr spectra of E-pent-2-ene and Z-pent-2-ene, H-1 nmr spectrum of E-pent-2-ene and Z-pent-2-ene, understanding the hydrogen-1 nmr spectrum of E-pent-2-ene and Z-pent-2-ene, explaining the line splitting patterns in the high resolution H-1 nmr spectra of E-pent-2-ene and Z-pent-2-ene, revising the H-1 nmr spectrum of E-pent-2-ene and Z-pent-2-ene, proton nmr of E-pent-2-ene and Z-pent-2-ene, ppm chemical shifts of the H-1 nmr spectrum of E-pent-2-ene and Z-pent-2-ene, 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 E-pent-2-ene and Z-pent-2-ene, how to work out the number of chemically different protons in the structure of the E-pent-2-ene and Z-pent-2-ene organic molecule, how to analyse the chemical shifts in the hydrogen-1 H-1 proton NMR spectrum of E-pent-2-ene and Z-pent-2-ene using the n+1 rule to explain the spin - spin coupling ine splitting in the proton nmr spectrum of E-pent-2-ene and Z-pent-2-ene deducing the nature of the protons from the chemical shifts ppm in the H-1 nmr spectrum of E-pent-2-ene and Z-pent-2-ene examining the 1H nmr spectrum of  E-pent-2-ene and Z-pent-2-ene analysing the 1-H nmr spectrum of E-pent-2-ene and Z-pent-2-ene how do you sketch and interpret the H-1 NMR spectrum of E-pent-2-ene and Z-pent-2-ene interpreting interpretation of the H-1 proton NMR spectrum of E-pent-2-ene and Z-pent-2-ene H-1 proton NMR spectra of the E/Z isomers of pent-2-ene cis/trans stereoisomers of 2-pentene H-1 proton NMR spectra of cis pent-2-ene trans pent-2-ene cis 2-pentene trans 2-pentene C5H10 How do you interpret the H-1 NMR spectrum of E/Z pent-2-ene (cis/trans isomers 2-pentene) How to interpret the H-1 NMR spectrum of E/Z pent-2-ene (cis/trans isomers 2-pentene) Explanatory diagram of the chemical shifts of the 1H H-1 proton NMR spectrum of the E/Z pent-2-ene (cis/trans isomers 2-pentene) molecule in terms of its molecular structure. Listing data of all the chemical shift peaks in ppm in the proton NMR spectrum of E/Z pent-2-ene (cis/trans isomers 2-pentene). How to explain the H-1 NMR spectrum of E/Z pent-2-ene (cis/trans isomers 2-pentene). The chemical shifts and  integrated values of the proton ratios in the 1-H NMR spectrum of the E/Z pent-2-ene (cis/trans isomers 2-pentene) molecule. How to work out the molecular structure of the E/Z pent-2-ene (cis/trans isomers 2-pentene) molecule from its proton NMR spectrum. The uses and distinctive features of the proton NMR spectrum of the E/Z pent-2-ene (cis/trans isomers 2-pentene) molecule explained. What does the H-1 proton NMR spectrum chemical shifts tell us about the structure and properties of the E/Z pent-2-ene (cis/trans isomers 2-pentene) molecule? explaining the spin-spin proton coupling effects in the 1H NMR spectrum of E/Z pent-2-ene (cis/trans isomers 2-pentene). interpretation diagram explaining the proton splitting pattern produced from the n+1 rule and the theoretical ratio of chemical shift δ and values of intensities for the proton NMR spectrum lines of E/Z pent-2-ene (cis/trans isomers 2-pentene)

Links associated with E-pent-2-ene and Z-pent-2-ene

The chemistry of ALKENES revision notes INDEX

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

The infrared spectra of the E/Z isomers of pent-2-ene (cis/trans isomers of 2-pentene)

The mass spectra of the E/Z isomers of pent-2-ene (cis/trans isomers of 2-pentene)

The C-13 NMR spectra of the E/Z isomers of pent-2-ene (cis/trans isomers of 2-pentene)

ALL SPECTROSCOPY INDEXES

STEREOISOMERISM general definition, E/Z (geometric/geometrical cis/trans) isomerism

All Advanced Organic Chemistry Notes

Use My Google search site box

Email doc b: chem55555@hotmail.com

Website content © Dr Phil Brown 2000+. All copyrights reserved on revision notes, images, quizzes, worksheets etc. Copying of Doc Brown's pre-university advanced level chemistry website material is NOT permitted. Exam revision summaries & references to science course specifications are unofficial. These organic chemistry revision notes on spectroscopy are suitable for use of pre-university students studying AQA advanced level chemistry, Edexcel advanced level chemistry, OCR advanced level chemistry, IB advanced level chemistry, WJEC (Eduqas) advanced level chemistry, CIE advanced level chemistry, CCEA advanced level chemistry, US grade 11-12 AP honors chemistry courses and they will also prove useful to 1st year undergraduate students of chemistry.

TOP OF PAGE