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A neutral tetraphosphacyclobutadiene ligand in cobalt(I) complexes
Shenglai Yao1, Nils Lindenmaier, Yun Xiong
1Technische Universität Berlin, Institute of Chemistry: Metalorganics and Inorganic Materials, Sekr. C2, Strasse des 17. Juni 135, 10623 Berlin (Germany) http://www.driess.tu-berlin.de.
Angewandte Chemie (International Ed. in English)
|December 6, 2014
Summary
This study reveals novel cobalt(I) complexes reacting with white phosphorus to form unique cyclo-P4 ligands. These complexes exhibit interesting redox behavior and electronic structures, offering new insights into phosphorus chemistry.
Area of Science:
- Organometallic Chemistry
- Inorganic Chemistry
- Phosphorus Chemistry
Background:
- Investigated the reactivity of newly synthesized β-diketiminato cobalt(I) complexes.
- Focused on reactions with white phosphorus, a key element in various chemical applications.
- Aimed to synthesize novel cobalt-phosphorus compounds with unique structural and electronic properties.
Purpose of the Study:
- To explore the unusual reactivity of β-diketiminato cobalt(I) complexes with white phosphorus.
- To synthesize and characterize the first cobalt(I) complexes featuring a neutral cyclo-P4 ligand.
- To investigate the redox chemistry and electronic structures of these novel cobalt-phosphorus compounds.
Main Methods:
- Synthesis of β-diketiminato cobalt(I) complexes.
- Reaction with white phosphorus to form cyclo-P4 cobalt complexes.
- Redox studies using cyclic voltammetry.
- Chemical reduction with potassium graphite.
- Characterization by NMR, EPR spectroscopy, and magnetic measurements.
- Theoretical elucidation using broken-symmetry DFT calculations.
Main Results:
- Successfully synthesized the first cobalt(I) complexes bearing a neutral cyclo-P4 ligand with a rectangular-planar structure.
- Investigated redox chemistry, leading to the isolation of monoanionic Co2P4 cores with a two-electron-reduced cyclo-P4(2-) ligand.
- Observed square-planar cyclo-P4(2-) structure and mixed-valent cobalt(I,II) sites in reduced complexes.
- Electronic structures confirmed by spectroscopic and magnetic data, consistent with DFT calculations.
Conclusions:
- Established a novel synthetic route to cobalt-cyclo-P4 complexes.
- Demonstrated unique redox activity and structural diversity of the cyclo-P4 ligand in cobalt complexes.
- Provided fundamental insights into the electronic structure and bonding of these organophosphorus cobalt compounds.
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