What is shielding and deshielding in NMR? Can you give me an example?
1 Answer
See explanation.
Explanation:
The basic principle of NMR is to apply an external magnetic field called
Electrons orbiting around the nucleus generate a small magnetic field that opposes
Shielding:
The higher the electron density around the nucleus, the higher the opposing magnetic field to
Deshielding:
If the electron density around a nucleus decreases, the opposing magnetic field becomes small and therefore, the nucleus feels more the external magnetic field
How would this affect the H NMR spectrum?
Let us compare the chemical shift of
Chlorine atom is an electronegative atom that will pull the electron density toward it ( electron withdrawing ), resulting in a deshielding of the hydrogen nucleus; an edit will fell higher external magnetic field
Hydrogen nucleus is shielded in the case of
Images source: Organic Chemistry-Janice Gorzynski Smith 3rd Ed