Question

Identify pairs of coupled protons in the compound whose COSY spectrum is shown below:

Short answer

Protons in ‘a’ is split by ‘c’; and those in ‘b’ is split by ‘d’.

Step-by-step solution

Step-by-Step SolutionStep 1: Draw a triangle showing the signals

The triangle is drawn in the spectrum which helps in easy identification of coupled protons. There is a cross peak in the triangle which tells about the coupled protons.

Finding coupled protons from the triangle

There are two points in the triangle, A and B.Point A denotes that protons in ‘a’ are split by protons in ‘c’. Point B denotes that the protons in ‘b’ are split by protons in ‘d’.