Inverted and fused expanded heteroporphyrins.

Area of Science:

• * Organic Chemistry
• * Supramolecular Chemistry
• * Materials Science

Background:

• * Expanded heteroporphyrins are large macrocycles (>17 atoms, >18 π electrons) comprising diverse heterocyclic rings.
• * These macrocycles exhibit structural flexibility, often adopting inverted conformations of pyrrole/heterocycle units.
• * Inverted conformations lead to two classes: N-inverted and hetero-atom inverted expanded heteroporphyrins.

Purpose of the Study:

• * To review the synthesis, structure, and properties of inverted and fused expanded heteroporphyrins.
• * To highlight the unique features arising from inverted and fused structures.
• * To cover compounds with varying numbers of heterocyclic rings (5 to 8+).

Main Methods:

• * Literature review focusing on synthesis strategies.
• * Structural analysis of inverted and fused macrocycles.
• * Examination of aromaticity, electronic, and coordination properties.

Main Results:

• * Inverted expanded heteroporphyrins display distinct structural, aromatic, electronic, and coordination behaviors.
• * Fused expanded heteroporphyrins, formed via intramolecular fusion, possess unique characteristics compared to their non-fused counterparts.
• * The study encompasses a range of expanded heteroporphyrins, from pentaphyrins to larger systems.

Conclusions:

• * Inverted and fused expanded heteroporphyrins represent a significant class of macrocyclic compounds with tunable properties.
• * Their unique conformations and electronic structures offer potential for novel applications.
• * Further research into their synthesis and properties will drive advancements in chemical and material sciences.