MPI für bioanorganische Chemie / MPI für bioanorganische Chemie |
|An Intermediate Cobalt(IV) Nitrido Complex and its N-Migratory Insertion Product.|
|Authors:||Zolnhofer, Eva M.; Käss, Martina; Khusniyarov, Marat M.; Heinemann, Frank W.; Maron, Laurent; van Gastel, Maurice; Bill, Eckhard; Meyer, Karsten|
|Date of Publication (YYYY-MM-DD):||2014|
|Title of Journal:||Journal of the American Chemical Society|
|Journal Abbrev.:||J. Am. Chem. Soc.|
|Issue / Number:||42|
|Review Status:||Internal review|
|Abstract / Description:||Low-temperature photolysis experiments (T = 10 K) on the tripodal azido complex [(BIMPNMes,Ad,Me)Co-II(N-3)] (1) were monitored by EPR spectroscopy and support the formation of an exceedingly reactive, high-valent Co nitrido species [(BIMPNMes,Ad,Me)Co-IV(N)] (2). Density functional theory calculations suggest a low-spin d(5), S = 1/2, electronic configuration of the central cobalt ion in 2 and, thus, are in line with the formulation of complex 2 as a genuine, low-spin Co(IV) nitride species. Although the reactivity of this species precludes handling above 50 K or isolation in the solid state, the N-migratory insertion product [(NH-BIMPNMes,Ad,Me)Co-II](BPh4) (3) is isolable and was reproducibly synthesized as well as fully characterized, including CHN elemental analysis, paramagnetic H-1 NMR, IR, UVvis, and EPR spectroscopy as well as SQUID magnetization and single-crystal X-ray crystallography studies. A computational analysis of the reaction pathway 2 -> 3 indicates that the reaction readily occurs via N-migratory insertion into the CoC bond (activation barrier of 2.2 kcal mol(1)). In addition to the unusual reactivity of the nitride 2, the resulting divalent cobalt complex 3 is a rare example of a trigonal pyramidal complex with four different donor ligands of a tetradentate chelatean N-heterocyclic carbene, a phenolate, an imine, and an aminebinding to a high-spin Co(II) ion. This renders complex 3 chiral-at-metal.|
|External Publication Status:||published|
|Communicated by:||N. N.|
|Affiliations:||MPI für bioanorganische Chemie|
|External Affiliations:||[Zolnhofer,E.M.; Käss,M.; Khusniyarov,M.M.; Heinemann,F.W.; Meyer,K.;]Univ.Erlangen Nürnberg, Dept.Chem.& Pharm., D-91058 Erlangen, Germany.
[Maron,L.;] Univ.Toulouse, F-31077 Toulouse, France.
|Identifiers:||ISI:000343686500065 [ID No:1] |
ISSN:0002-7863 [ID No:2]
DOI:10.1021/ja508144j [ID No:3]
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