Aromaticity

Aromatic Compounds

Function/Purpose:

Criteria

• 1) Structure must be cyclic containing CONJUGATED pi bonds
• 2) Each atom must have an unhybridized p orbital
  • sp2 or sp
• 3) Unhybridized orbitals must overlp to form a continuous
  • FULLY CONJUGATED and CYLCIC SYSTEM
• 4) Delocalization of pi electrons must LOWER the electronic energy
  • Focus on unfavorable charges if heterocyclic

Types

• Aromatic - lowers electronic energy
• Antiaromatic - increases electronic energy

Concepts:

• Conjugated Systems

Terminology:

• Aromatic: meets all the criteria above
• Antiaromatic: meets the first three criteria
• Nonaromatic: cyclic compound that does not havea continuous overlapping pi bonds/conjugated pi bonds

Additional Links:

• Wikipeida