Description
Molybdenum (II) acetate is a coordination compound with the formula Mo
2(O
2CCH
3)
4. It is a yellow, diamagnetic, air-stable solid that is slightly soluble in organic solvents. Molybdenum(II) acetate is an iconic example of a compound with a metal-metal quadruple bond.
Chemical Properties
yellow to greenish needle-like crystals or
Physical properties
Molybdenum (II) Acetate adopts the same Chinese lantern structure as related acetate dimers such as rhodium (II) acetate, copper (II) acetate, and chromium (II) acetate. Each Mo(II) center in Mo2(O2CCH3)4 has four d valence electrons. These eight d-electrons form one σ, two π bonds, and one δ bond, creating a bonding electron configuration of σ2π4δ2. Each of these bonds are formed by the overlapping of pairs of d orbitals.The four acetate groups bridge the two metal centers. The Mo-O bond between each Mo(II) center and O atom from acetate has a distance of 2.119 Å, and the Mo-Mo distance between the two metal centers is 2.0934 Å.
Uses
Molybdenum(II) acetate dimer is generally used as an intermediate compound in a process to form other quadruply bonded molybdenum compounds.
Preparation
Mo
2(O
2CCH
3)
4is prepared by treating molybdenum hexa carbonyl (Mo (CO)
6) with acetic acid. The process strips CO ligands from hexacarbonyl results in the oxidation of Mo (0) to Mo (II).
2 Mo(CO)
6 + 4 HO
2CCH
3 → Mo
2(O
2CCH
3)
4 + 12 CO + 2 H
2 Trinuclear clusters are byproducts.
The reaction of HO
2CCH
3 and Mo(CO)
6 was first investigated by Bannister et al. in 1960. At the time, quadruple metal-metal bonds had not yet been discovered, so these authors proposed that "Mo(O
2CCH
3)
2 was tetrahedral. This perspective changed with Mason's characterization .
Application
Mo
2(O
2CCH
3)
4 is generally used as an intermediate compound in a process to form other quadruply bonded molybdenum compounds The acetate ligands can be replaced to give new compounds such as [Mo
2Cl
8]
4- and Mo
2Cl
4[P(C
4H
9)
3]
4.
