Bis(cyclooctadiene)nickel(0) is the organonickel compound with the formula Ni(C8H12)2, also written Ni(cod)2. It is a diamagnetic coordination complex featuring tetrahedral nickel(0) bound to the alkene groups in two 1,5-cyclooctadiene ligands. This highly air-sensitive yellow solid is a common source of Ni(0) in chemical synthesis.

Preparation and properties

The complex is prepared by reduction of anhydrous nickel(II) acetylacetonate in the presence of the diolefin: Ni(cod)2 is moderately soluble in several organic solvents. If exposed to air, the solid oxidizes in a few minutes to nickel(II) oxide. As a result, this compound is generally handled in a glovebox.

Reactions

The reactivity of Ni(cod)2 has been extensively examined. One or both 1,5-cyclooctadiene ligands are readily displaced by phosphines, phosphites, bipyridine, and isocyanides. Oxidation gives the highly reactive monocation, which can be isolated when using weakly coordinating anions: Of its many catalytic reactions, Ni(cod)2 in the presence of phosphine ligands catalyzes the demethoxylation of anisoles by hydrosilanes: