What is shielding and deshielding in NMR? Can you give me an example?
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
The higher the electron density around the nucleus, the higher the opposing magnetic field to
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