Diphenylacetylene

Diphenylacetylene is the chemical compound C6H5C≡CC6H5. The molecule consists of phenyl groups attached to both ends of an alkyne. It is a colorless crystalline material that is widely used as a building block in organic and as a ligand organometallic chemistry.

Preparation
Several preparations for this compound exist:
 * one being from benzil which is condensed with hydrazine to give the bis(hydrazone) that in turn suffers oxidation with mercury oxide HgO.
 * The compound is usually prepared from stilbene by bromination dehydrohalogenation sequence, but the product can be contaminated with stilbene, which is difficult to remove.
 * One methods starts from iodobenzene and the copper salt of phenylacetylene in the Castro-Stephens coupling

Interesting derivatives

 * Reaction of Ph2C2 with tetraphenyl substituted cyclopentadienone results in the formation of hexaphenylbenzene.
 * Reaction of Ph2C2 with benzal chloride in the presence of potassium t-butoxide affords the 3-alkoxycyclopropene which coverts to the cyclopropenium ion.