“…In these and other similar studies, different groups were found to influence the chemical shifts in different ways through different mechanisms. Some of the contributing factors are electronegativity (4), hyperconjugation (10,11,14), resonance (7), molecular dipoles (2) , and diamagnetic anisotropy effects (6,8,12,13,15). An excellent example of the effect of electron withdrawing groups is the correlation between the NMR resonance line positions for CH3 and CH2 protons of ethyl halides and the Huggins electronegativity values (4).…”