The effect of tetra-n-butylammonium bromide on the proton magnetic resonance of 1-X-2,4-dinitrobenzenes

The chemical shifts of the ring protons of 1-X-2,4-dinitrobenzenes are changed with the addition of tetrabutylammonium bromide. In general, the chemical shift of proton 3 decreases with salt addition, that of proton 5 may increase or decrease, while that of proton 6 increases. Where X is an oxygen containing group, the changes are somewhat more pronounced.