Two-dimensional NMR spectroscopy

In this experiment we observe the coupling J between the X nuclei and the protons which are bound to them (Fig. 27). A coupled normal 1D spectrum XH may be very difficult to explain. This is due to the intercrossing of the multiplets^[1]. For simplifying the spectra, we will spread the coupling data in the dimension and the informations arising from the chemical shifts in the dimension.

Fig. 27 : The 2D J-resolved heteronuclear pulse sequence

The results are given for the saccharine (Fig. 29). The carbon (108 ppm) is a quaternary one because we may observe only one spot devoided of coupling. The carbon (95 ppm) is a CH because there are two correlation spots. Moreover, the coupling constant between this and this is of 80 Hz approximately (Spectrum 13 and 14).

Spectrum 13 : Heteronuclear 2D J-resolved

Spectrum 14 

The Heteronuclear correlation of chemical shifts in inverse detection.