Oxidation-induced double aromaticity in periodo-polycyclic hydrocarbons

Area of Science:

• Organic Chemistry
• Theoretical Chemistry
• Quantum Chemistry

Background:

• Hexaiodobenzene ([C6I6]2+) is a known double aromatic molecule with both pi- and sigma-aromaticity.
• Understanding the origins of double aromaticity is crucial for designing novel aromatic systems.

Purpose of the Study:

• To systematically investigate the origin of double aromaticity in periodo-monocyclic molecules and their doubly oxidized forms.
• To explore how the central carbon atom ring's size and aromaticity influence the double aromaticity of oxidized structures.
• To apply these findings to model polycyclic aromatic hydrocarbons and induce double aromaticity through oxidation.

Main Methods:

• Computational modeling and theoretical calculations were used to analyze the electronic structure of various periodo-monocyclic molecules.
• Systematic variation of the central carbon ring size and iodine ring structure.
• Application of theoretical insights to design and model polycyclic aromatic hydrocarbon derivatives.

Main Results:

• The study identified key factors governing double aromaticity, including the size of the central carbon ring and the degree of σ-electron delocalization in the iodine framework.
• Periodo-monocyclic systems serve as excellent models for understanding the fundamental principles of double aromaticity.
• Oxidation of polycyclic aromatic hydrocarbons can induce σ-electron cyclic delocalization, leading to double aromaticity.

Conclusions:

• The size and aromaticity of the central carbon ring are critical determinants of double aromaticity in oxidized molecules.
• Oxidation-induced σ-electron delocalization in macrocyclic iodine rings can confer double aromaticity upon polycyclic aromatic systems.
• This research provides a framework for designing novel molecules with enhanced aromatic properties.