1H-1H couplings arise from influences on a proton’s magnetic field induced by the magnetic field of a neighbouring proton(s). As a proton experiences coupling from a neighbouring proton, so too is the coupling reciprocated to the neighbouring proton(s). By measuring the J-coupling for each splitting pattern, the proton connectivity information can be deduced.
By comparing the J-coupling for each splitting pattern in the 1H NMR below, roughly +/- 0.2 Hz, one can determine which multiplets pair up. Based on the pairing information, we can deduce that the proton is within proximity of its pair.
Coupled protons are:
Multiplets A and C = green line
Multiplets B and C = orange line
Multiplets D and C = purple line.
Multiplets E and C = red line.
Multiplets D and E = black line.