Amines

Structure: C–NR₂ (R = H or alkyl/aryl) Hybridization: sp³ at nitrogen (lone pair occupies the fourth position) Geometry: Trigonal pyramidal, ~107° Polarity: Polar; primary and secondary amines are hydrogen bond donors, and all amines are hydrogen bond acceptors Typical reactivity: The nitrogen lone pair is both basic (Chapter 3) and strongly nucleophilic — amines are common nucleophiles in substitution and acyl substitution reactions.

Amides

See Carboxylic Acids and Their Derivatives, above. Amides sit at the intersection of the oxygen- and nitrogen-containing families: the carbonyl places them among the acyl derivatives, while the nitrogen places them among biologically central nitrogen groups (proteins, peptides).

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