Stabilization of a Two‐Coordinate Mononuclear Cobalt(0) Compound |
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| Authors: | Dr Kartik Chandra Mondal Dr Sudipta Roy Dr Susmita De Dr Pattiyil Parameswaran Dr Birger Dittrich Dr Fabian Ehret Prof Dr Wolfgang Kaim Prof Dr Herbert W Roesky |
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| Affiliation: | 1. Institut für Anorganische Chemie, Universit?t G?ttingen, Tammannstrasse 4, 37077 G?ttingen (Germany);2. Dept. of Chemistry, National Institute of Technology Calicut, NIT Campus P.O., Kozhikhode ‐ 673 601, Kerala (India);3. Universit?t Hamburg, Martin‐Luther‐King‐Platz 6, 20146‐Hamburg (Germany);4. Universit?t Stuttgart, Institut für Anorganische Chemie, Pfaffenwaldring 55, 70569 Stuttgart (Germany) |
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| Abstract: | Compound (Me2‐cAAC:)2Co0 ( 2 ; Me2‐cAAC:=cyclic (alkyl) amino carbene; :C(CH2)(CMe2)2N‐2,6‐iPr2C6H3) was synthesized by the reduction of the precursor (Me2‐cAAC:)2CoICl ( 1 ) with KC8 in THF. The cyclic voltammogram of 1 exhibited one‐electron reduction, which suggests that synthesis of a bent 2‐metallaallene ( 2 ) from 1 should be possible. Compound 2 contains one cobalt atom in the formal oxidation state zero, which is stabilized by two Me2‐cAAC: ligands. Bond lengths from X‐ray diffraction are 1.871(2) and 1.877(2) Å with a C‐Co‐C bond angle of 170.12(8)°. The EPR spectrum of 2 exhibited a broad resonance attributed to the unique quasi‐linear structure, which favors near degeneracy and gives rise to very rapid relaxation conditions. The cAAC?Co bond in 2 can be considered as a typical Dewar–Chatt–Duncanson type of bonding, which in turn retains 2.5 electron pairs on the Co atom as nonbonding electrons. |
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| Keywords: | carbenes cobalt density functional calculations EPR spectroscopy synthetic methods |
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