HOW TO DRAW A COUPLING/SPLITTING TREE IN NMR?

  

Coupling tree is a pattern developed as a result of the splitting of signals in 1H-NMR due to spin-spin coupling. The tree tells us about the splitting pattern of the signal and also helps in calculation of the coupling constant.

Let’s see how coupling trees are drawn for different signals.

 

DOUBLET

A doublet is obtained when a signal is split into two.

 

TRIPLET

Triplet is a signal split into three

 

QUARTET

When a signal is split into four, it is known as quartet

 

DOUBLE DOUBLET/DOUBLET OF A DOUBLET

When a signal first splits into two and then each arm of that doublet splits further into two lines, a double doublet (dd) is observed. In this case we have two coupling constants, one each for the two doublets.

 

TRIPLET OF A DOUBLET

When a signal first splits into two and then the doublet further splits into two tirplets, a triplet of a doublet (dt) is obtained. Again we have two coupling constants. The larger J belongs to the doublet.

 

DOUBLET OF A TRIPLET

When a triplet splits into three doublets, doublet of a triplet (td) arises. In this case the larger J belongs to the triplet.