A Structurally Characterised Pair of Dicobalt(III) Peroxo/Superoxo Complexes with C2-Symmetrical Tetrapodal Pentadentate Amine Ligands, and Some Reactivity en route
✍ Scribed by Stefan Schmidt; Frank W. Heinemann; Andreas Grohmann
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 436 KB
- Volume
- 2000
- Category
- Article
- ISSN
- 1434-1948
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✦ Synopsis
The tetrapodal pentaamine ligand 2,6-bis(1Ј,3Ј-diamino-2Јmethylprop-2Јyl)pyridine (pyN 4 , 1) provides square-pyramidal coordinated cobalt(II) building blocks, which have been used in the synthesis of the singly-bridged dicobalt(III) µ 2η 1 :η 1 -peroxo and superoxo complexes [(1)Co-O 2 -Co(1)] 4+/5+ , isolated as the chloride, bromide, and mixed chloride/dithionate and bromide/dithionate salts. The peroxo complex is accessible by the classical route involving oxygenation of [(pyN 4 )Co II ], but has also been obtained from a cobalt(III) precursor in air, which implies that the pentaamine 1 acts as a multi-electron reductant. Oxidation of the peroxo complex with chlorine generated in situ from an HCl/H 2 O 2 mixture (H 2 O 2 derived from partial peroxo complex hydrolysis) generates the superoxo complex. Both cations have highly symmetrical solid state structures, locked in transoid Co-O-O-Co conformations by two pairs of intramolecular hydrogen bonds. Each involves two protons in the equatorial [a] Institut für Anorganische Chemie,