Cyclopentadienylmolybdenum tricarbonyl dimer is the chemical compound with the formula Cp2Mo2(CO)6, where Cp is C5H5. A dark red solid, it has been the subject of much research although it has no practical uses.
The molecule exists in two rotamers, gauche and anti.[1] The six CO ligands are terminal and the Mo-Mo bond distance is 3.2325 Å.[2] The compound is prepared by treatment of molybdenum hexacarbonyl with sodium cyclopentadienide followed by oxidation of the resulting NaMo(CO)3(C5H5).[3] Other methods have been developed starting with Mo(CO)3(CH3CN)3 instead of Mo(CO)6.[4]
Thermolysis of this compound in hot solution of diglyme (bis(2-methoxyethyl)ether) results in decarbonylation, giving the tetracarbonyl,[4] which has a formal triple bond between the Mo centers (dMoMo = 2.448 Å):[5]
(C5H5)2Mo2(CO)6 → (C5H5)2Mo2(CO)4 + 2 COThe resulting cyclopentadienylmolybdenum dicarbonyl dimer in turn binds a variety of substrates across the metal-metal triple bond.