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One Ligand, Three Roles: L-, X-, and Z-Type Coordination at Nitrogen
Liav Leiboviz1, Alexander Kaushansky1, Itai Zvieli1
1Schulich Faculty of Chemistry and Resnick Sustainability Center for Catalysis, Technion - Israel Institute of Technology, Haifa, Israel.
Angewandte Chemie (International Ed. in English)
|July 21, 2026
Summary
Researchers developed novel nitrogen-based ligands exhibiting multimodal coordination (L-, X-, and Z-type). These N-heterocyclic nitrenium ligands reversibly switch between donor and acceptor modes, enabling "redox-by-coordination".
Area of Science:
- Coordination Chemistry
- Organometallic Chemistry
- Ligand Design
Background:
- Nitrogen ligands typically exhibit L- and X-type donor behavior in coordination chemistry.
- A need exists for novel nitrogen ligands with diverse coordination capabilities.
Purpose of the Study:
- To introduce a new class of nitrogen ligands with multimodal coordination behavior.
- To demonstrate reversible switching between L- and X-type coordination states.
- To establish nitrogen-based Z-ligands and the concept of "redox-by-coordination".
Main Methods:
- Synthesis of N-heterocyclic nitrenium (NHN) frameworks.
- X-ray crystallography to confirm coordination modes.
- Computational analysis to elucidate electronic properties and bonding.
Main Results:
- NHN ligands exhibit multimodal L-, X-, and Z-type coordination.
- Reversible switching between L- and X-type states was demonstrated.
- The concept of "redox-by-coordination" was introduced, where metal oxidation state changes with solvent coordination.
Conclusions:
- NHN ligands represent a fundamentally new class of nitrogen-based ligands.
- These ligands offer unprecedented control over metal oxidation states through coordination.
- The findings open new avenues in coordination chemistry and catalyst design.
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