Charge frustration in ligand design and functional group transfer

Area of Science:

• Coordination Chemistry
• Organic Chemistry
• Materials Science

Background:

• Molecules with multiple resonance structures, such as heterocumulenes and mesoionics, are vital in diverse chemical applications.
• Ambidentate or ambiphilic ligands in coordination chemistry were historically limited and considered curiosities.

Purpose of the Study:

• To present 'charge frustration' (ambiphilicity) as a unifying principle for ligand design and functional group transfer.
• To review the historical development, electronic structures, and applications of organic zwitterions and zwitterionic ligands.
• To highlight novel approaches in single-atom transfer and emerging areas like bond activation and reversible electron chemistry.

Main Methods:

• Historical review of organic zwitterions and their electronic properties.
• Discussion of zwitterionic ligands, including ylidic and redox-active types, and their metal complexes.
• Exploration of new methods for single-atom transfer and donor-acceptor ligand systems.

Main Results:

• Ambiphilicity, or charge frustration, provides a powerful framework for designing functional ligands.
• Zwitterionic ligands exhibit diverse coordination behaviors and enable unique chemical transformations.
• Novel strategies for single-atom transfer and reversible redox processes are emerging.

Conclusions:

• Charge frustration is a key concept for understanding and designing advanced functional molecules and ligands.
• Zwitterionic and ambiphilic ligands offer significant potential in catalysis, sensing, and materials science.
• Future research directions include bond activation and the development of switchable electronic systems.