Diphosphines, sometimes called bisphosphanes, are organophosphorus compounds most commonly used as bidentate phosphine ligands in inorganic and organometallic chemistry.
The short-chain diphosphine dppm tends to promote metal-metal interactions as illustrated by A-frame complexes.
When the two phosphine substituents are linked by two to four carbon centres, the resulting ligands often chelate rings with a single metal.
A common diphosphine ligand is dppe, which forms a five-membered chelate ring with most metals.
Some diphosphines, such as the extraordinary case of tBu2P(CH2)10PtBu2, give macrocyclic complexes with as many as 72 atoms in a ring.