14cyclooctadiene

1,4-cyclooctadiene, often abbreviated as COD, is a cyclic diene with the chemical formula C8H12. It is an isomer of cyclooctadiene, with the two double bonds located at positions 1 and 4 of the eight-membered ring. At room temperature, it is a colorless liquid with a characteristic odor. It is typically produced through the cyclodimerization of butadiene.

COD is a versatile organic compound and finds significant use as a ligand in organometallic chemistry. Its bidentate nature, with the two double bonds capable of coordinating to a metal center, makes it a common component in the synthesis of various transition metal complexes. These complexes are employed as catalysts in a range of organic transformations, including polymerization reactions, hydrogenation, and cross-coupling reactions. For example, nickel(0) complexes with COD are well-known catalysts.

Due to its reactivity, 1,4-cyclooctadiene is susceptible to addition reactions across its double bonds. It can undergo hydrogenation to form cyclooctane, or undergo Diels-Alder reactions under specific conditions. Its stability is moderate, and it is generally stored under an inert atmosphere to prevent oxidation. Safety precautions should be taken when handling 1,4-cyclooctadiene, as it is a flammable liquid and may cause irritation.