Main Content
Introduction of Nuclear Magnetic Resonance (NMR) Analysis
Modern Research Methods in Polymer Science
One Dimensional NMRs
1H NMR
13C NMR
Others: 15N/19F/29Si/31P NMR
Two Dimensional NMRs
Solid-State NMR
1H NMR
Function Advantages
(1) To determine the micro chemical structure(2) To test the purity of compounds(3) To determine the proportion of each component in the mixture
(1) Analyzing the material
molecular configuration space
(2) Measuring without destroying
samples
(3) Precise Information
1
2
3 1. Chemical Shift
2. Spin Splitting
3. Peak Area
O
O
C=O
13C NMR
Function(1) Determination of molecular
structure
(2) Analysis of organic compound structure
Main differences between 13C-NMR and 1H-NMR13C-NMR 1H-NMR
Study of spin changes of carbon nuclear
Chemical shift ranges from 0-240 ppm
The process is very slow Pulse-fourier transform
technique is used
Study of spin changes of proton nuclear
Chemical shift ranges from 0-14 ppm
The process is very fast Continuous wave method is
used
Two Dimensional NMRs
Function
(1) Analyze the complex organic molecules
(2) Detect the three dimensional structure of polymers in the solution
(3) Research the dynamic procedure of the molecules
Advantages
(1) Putting some parameter of NMR (chemical shift (δ)、 coupling constant( J) and so on) in a two-dimensional plane
(2) Decreasing the overlap of the spectral line
(3) Providing new information about nuclear spin
J resolved spectroscopy
chemical shift correlation spectroscopy
multiple quantum spectroscopy
core
2D-NMR
homonuclear couple:1H-1H COSY
heterocaryosis couple:HMBC、HMQC
NOE:ROESY、NOESY
chemical exchange
Two Dimensional NMRs
Solid-State NMR
1. Some samples are not dissolved.
2. Some samples can be dissolved, but the structure could be changed in solvent.
3. Understand the structural changes from liquid to solid.
4. As an important supplement of X – ray.
5. Solid state nuclear magnetic resonance spectroscopy can provide solid state structure of material in the state of aggregation, phase structure, molecular motion information, interaction, etc.
6. The advantage of solid state NMR is to keep the solid state of matter.