HOW TO DRAW A COUPLING 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.

Coupling Tree for Doublet

TRIPLET
Triplet is a signal split into three

Coupling Tree for Triplet

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

Coupling Tree for 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.

Coupling Tree for Double Doublet

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.

Coupling Tree for Triplet of a 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.

Coupling Tree for Doublet of a Triplet