Nuclear Magnetic Resonance NMR Spectroscopy Nuclear Magnetic Resonance NMR Spectroscopy Shovan Sarker Biochemistry & Moleculer Biology SUST

What is NMR What is NMR  NMR is a special kind of spectroscopy technique by which we can identify different chemical or physical properties of organic or inorganic molecules & their structure.  It is a research technique which exploits the magnetic properties of certain atomic nuclei.

Types of NMR Types of NMR  Two common types of NMR spectroscopy are used to characterize organic structure. H NMR C NMR

How does it work How does it work  NMR spectroscopy exploits the idea of spinning & the feature of nuclei as a magnet.  Proton can spin & due to the spinning property of proton it can behave like a magnet.  NMR spectroscopy operates by applying a magnetic field to nuclei and then measuring the amount of energy necessary to put various nuclei in resonance.

Consider a H atom, it has one proton. And the very proton has a spin. Because of the spin the proton behave a magnet & it has two pole.

Not every molecule or atom will act like a magnet, only a few. Any atom of this characteristics will behave like a magnet.

Every magnet has a two pole. From now I will consider this as a magnet & the arrow pointing towards the north so opposite site pointing to the south.

What happens in NMR machine Magnets can affect the orientation of other magnets. Inside of a NMR machine an external magnetic field has produced.

So in the presence of applied magnetic field the magnet will spin & change the orientation. This spin is called alpha spin.

But not always the alpha spin is occurred so easily. Because of shielding the proton of the right side not gonna change it’s orientation.

We can also get a beta spin. But this situation is only possible if we put some extra energy as electromagnetic radiation.

If we do the same thing for the shielded proton, the beta spin takes for the proton takes less energy.

The spinning of the H nuclei, we can call this resonance. And to resonance take place energy is needed. Here the H atom of the left takes less energy because it turns very little & gone to the beta state.

Here for two atom we get two peak.

We will get different kind of spectra because of shielding.

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