Embedding a Planar Hypercoordinate Carbon Atom into a [4n+2] π-System.

Area of Science:

• Organic Chemistry
• Computational Chemistry
• Materials Science

Background:

• Hypercoordinate carbon compounds are rare and typically exhibit non-planar geometries.
• Aromatic hydrocarbons are fundamental building blocks in organic chemistry with tunable electronic properties.

Purpose of the Study:

• To rationally design novel global minimum energy structures with planar hypercoordinate carbon atoms.
• To explore the incorporation of planar tetra- or pentacoordinate carbon centers into aromatic hydrocarbon frameworks.
• To investigate the electronic and mechanical effects of incorporating these unique carbon centers.

Main Methods:

• Utilizing computational chemistry methods to predict and design stable molecular structures.
• Employing a strategy of replacing three consecutive hydrogen atoms in aromatic hydrocarbons with less electronegative groups.
• Forming multicenter sigma (σ)-bonds with the planar hypercoordinate carbon atom.
• Analyzing the participation of these structures in pi (π)-electron delocalization.

Main Results:

• Seventeen new putative global minimum energy structures containing planar tetra- or pentacoordinate carbon atoms were designed.
• These structures are embedded within aromatic hydrocarbon frameworks.
• The strategy successfully integrated hypercoordinate carbon centers while maintaining aromaticity and π-electron delocalization.
• The designed structures exhibit enhanced mechanical and electronic properties.

Conclusions:

• A rational design strategy for creating planar hypercoordinate carbon centers in aromatic hydrocarbons has been established.
• This method allows for the synthesis of diverse new compounds with unique electronic and mechanical characteristics.
• The approach holds potential for broader applications in designing novel molecular architectures and materials.