using proton nmr
DESCRIPTION
Using Proton NMR. How many Proton environments?. How many Proton environments?. How many Proton environments?. How many Proton environments?. Proton NMR Spectra. Number of environments = number of peaks Number of protons in environment = relative peak area ( integral) - PowerPoint PPT PresentationTRANSCRIPT
Using Proton NMR
How many Proton environments?
How many Proton environments?
How many Proton environments?
How many Proton environments?
Proton NMR Spectra
• Number of environments = number of peaks• Number of protons in environment = relative
peak area (integral)• Number of protons on neighbouring carbon =
splitting pattern (eg. doublet, triplet)• Type of proton environment = chemical shift
(compare with datasheet)
1H – NMR C2 H4 O
Quartet
Doublet
1 3 Integral
9.8 ppm
2.2 ppm
Ethanal
1H – NMR C3H8O Quartet
Septet (7)
Singlet
Integral 1 1 6
4.0 ppm
2.2ppm
1.2ppm
2-propanol
Integral 2 3 3
1H – NMR C4H8O2
Triplet
Quartet
Singlet
Ethyl ethanoate
4.1 ppm
2.0ppm
1.3ppm
Draw a Proton NMR to represent 1-Bromopropane – label with chemical shift, splitting pattern and relative integration
Draw a Proton NMR to represent 1-Bromopropane
Draw a Proton NMR to represent Butanoic acid – label with chemical shift, splitting pattern and relative integration
Draw a Proton NMR to represent Butanoic acid
O H
H C
H
O H
C
O
12
energyabsorbed
chem ical sh ift /
11 10 9 8 7 6 5 4 3 2 1 0
Sketch the 1H NMR spectrum of compound X (see right) and label the relative peak areas. Label any peaks that would be lost from the spectrum on shaking with D2O.
[4]
2 proton peak at δ = 3.3-4.3 – singlet (-CH2-) 11 proton peak at δ = 3.5-5.5 – singlet (-OH) 11 proton peak at δ = 11.0-11.7 – singlet (-COOH) 1
(ranges of chemical shift (δ) values taken from data sheet)• penalise each error once only• ignore peak areas/heights unless incorrectly labelled
Labelled diagram of the structure of G proposed by the student may be used to provide evidence for the positioning of peaks on the sketched spectrum.
Both OH and COOH protons disappear on shaking with D2O 1
O H
H C
H
O H
C
O