Bis(cyclooctadiene)nickel(0)

Bis(cyclooctadiene)nickel(0) is the organometallic compound with the formula Ni(C₈H₁₂)₂. This air-sensitive yellow solid is a common source of Ni(0) in chemical synthesis.

Ni(cod)₂, as it is commonly abbreviated, is a diamagnetic coordination complex featuring tetrahedral nickel(0) bound to the alkene groups in two 1,5-cyclooctadiene ligands. The complex is prepared by reduction of anhydrous nickel(II) acetylacetonate in the presence of the diolefin:

1/3 [Ni₃(acac)₆] + 2 cod + 2 AlEt₃ → Ni(cod)₂ + 2 acacAlEt₂ + C₂H₆ + C₂H₄

Ni(cod)₂ is moderately soluble in benzene and THF. The cod ligands are easily displaced by phosphines, phosphites, and isocyanides.