C8953
NMR structural analysis - seminar
Vector model of NMR experiments + 1D spectra
Jan Novotný
novotnyjan@mail.muni.cz
March 15, 2017
1H NMR spectrum of naringenine
Basics of 1D FT spectroscopy
Draw the expected vector model of following simple pulse sequences
(right-handed system, B0 in +z direction:)
� 90−x :
� 90+y − Ωτ = π/2:
� 90+x − Ωτ = π/3 − 180+x − Ωτ = π/3:
� 90+x − Ωτ = π/3 − 180+y − Ωτ = π/3:
Basics of 1D FT spectroscopy
Draw FT representation of attached FID
records (reciever is located in the +y
direction):
Basics of 1D FT spectroscopy
Draw FT representation of vector models
(in rotating frame, reciever is located in the
+y direction):
Heteronuclear spin echo of 13
C-1
H3 group
By using vector diagrams determine the result of attached pulse sequence. First
realize what is the evolution of 13C signal resulting from offset? CPD=composite pulse
decoupling
APT - Attached Proton Test
based on heteronuclear spin echo
� t1 = 1/1JCH
13
C signals are differentiated according to the number of directly
bound 1
H
� Cq, CH2 positive
� CH, CH3 negative
Evolution of signal governed by the value of 1
JCH =⇒ reflected by
the intensity of APT signal
90x 180y
180
H-1
C-13 acq
dec
t1
-1
-0.5
0
0.5
1
0 0.5 1 1.5 2
Relativeintensity
t1 (1/1
JCH)
Cq
CH
CH2
CH3
13
C APT Cinnamic acid
13
C APT of Nicotine
13
C APT 4
Cq Cq CH2
1
H-13
C DEPT spectrum
http://www.akoci.uni-hannover.de/ak-duddeck/pdf/pdf-master-wirk-nat
Next topic
2D spectroscopy