# Why are amidines so much more basic than amides?

Both delocalize the added proton. Is it because the bond lengths in amidines are the same, or perhaps because oxygen is more electronegative than nitrogen and thus is more reluctant at keeping the proton? But how can that explane the huge difference in basicity between amidines and amides (resp $12$/$13$ versus $-1$/$0$ of $\mathrm{p}K_\mathrm{aH}$)?

• Since amides are protonated to oxygen, the question you're asking can be rephrased as 'why oxygen is easier protonated then nitrogen' . The easiest explanation is 'electronegativity'. When protonated, oxygen has to share an electron with proton, and it is much easier for nitrogen than for oxygen. – permeakra Jun 29 '14 at 22:32