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Cofacial dicobalt complex of a binucleating hexacarboxamide cryptand ligand
Glen E Alliger1, Peter Müller, Christopher C Cummins
1Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
Inorganic Chemistry
|March 27, 2010
Summary
Researchers developed a novel hexacarboxamide cryptand, a hexaanionic N donor, for binuclear cobalt complexes. This new cryptate exhibits unique structural features and reactivity, including forming bridging cyanide complexes.
Area of Science:
- Coordination Chemistry
- Supramolecular Chemistry
- Materials Science
Background:
- Cryptands are macrocyclic compounds known for their ability to encapsulate ions.
- Hexaanionic ligands are less common in coordination chemistry.
- Binuclear metal complexes offer unique electronic and magnetic properties.
Purpose of the Study:
- To synthesize and characterize a novel hexacarboxamide cryptand.
- To explore its use as a binucleating ligand for cobalt(II) centers.
- To investigate the structural and reactive properties of the resulting dicobalt cryptate.
Main Methods:
- Multi-step organic synthesis of the hexacarboxamide cryptand.
- High-dilution techniques for improved yield.
- Metalation with cobalt(II) acetate.
- X-ray crystallography for solid-state structure determination.
- Reactivity studies with potassium cyanide.
Main Results:
- Successful synthesis of the hexacarboxamide cryptand in 8% overall yield.
- Formation of a binuclear cobalt(II) cryptate complex.
- Crystal structure revealed an intermetallic void exceeding 6.4 Å.
- Demonstrated reactivity by forming a bridging cyanide complex.
Conclusions:
- Hexacarboxamide cryptands represent a new class of hexaanionic N-donor ligands for metal coordination.
- The synthesized dicobalt cryptate possesses a significant intermetallic void.
- This novel cryptate system exhibits interesting reactivity, enabling further functionalization.
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