Physical and Chemical Properties

What are three physical properties of amides?

1. Basicity
   • Amines are weak bases
   • Electron withdrawing groups decrease basicity (aromatic rings, $ŠNO_{2}$), electron donating groups increase basicity (e.g. $ŠOH$, $- CH_{3}$)

2. Lone pair of electrons
   • Hydrogen bonding

Table 52.1: Hydrogen bonding by 1$^{o}$, 2$^{o}$ and 3$^{o}$ amines.

	Can form hydrogen bonds	Can form hydrogen bonds
	with each other	with $H_{2}O$
1$^{o}$ amines	$\star$	$\star$
2$^{o}$ amines	$\star$	$\star$
3$^{o}$ amines		$\star$

What is the infrared absorption of the amine group ($-NH$)?

Table 52.2: Infrared absorption of the hydroxyl group ($C-OH$).

Bond Frequency	($cm^{-1}$)
N-H	$\sim$3300