A Dicobalt Coordination Complex with a Short Cobalt‐Cobalt Distance

Abstract The existence of a metal‐metal bond in organometallic and coordination complexes is a very important aspect. Metal‐carbonyl, carbene‐metal‐carbonyl and metal‐carbene complexes were studied for having this feature. Herein, an air stable dark green color dicobalt coordination complex [Co(III) 2 (hep) 3 (N 3 ) 3 ] (1) [hepH = 2‐(2‐ethylhydroxy)pyridine] with three μ‐alkoxide bridges has been synthesized and characterized by X‐ray single crystal diffraction, NMR and UV/vis spectroscopy. Complex 1 has a short Co⋅⋅⋅Co distance (2.595(6) Å) and thus it has been studied by theoretical calculations. QTAIM (quantum theory of atoms in molecules) as well as EDA‐NOCV analysis (energy decomposition analysis ‐ natural orbitals for chemical valence) do not indicate any significant metal‐metal interaction. The bonding in 1 can be best represented by the interaction of two alkokxy bridged valence electrons fragment Co(III)(hep) 2 N 3 (3d 6 ) with Co(III)(hep)(N 3 ) 2 (3d 6 ) where the donation of the lone pair of electrons from three bridging O hep ‐atoms stabilizes the dinuclear Co(III) complex. Additionally, thermolysis of 1 at 550 o C led to the formation sponge like Co 3 O 4 oxide.