:Cyclopentadienylmolybdenum tricarbonyl dimer
{{chembox
| Watchedfields = changed
| verifiedrevid = 427297729
| ImageFile1 = CP2Mo2(CO)6imp.svg
| ImageFile2 = Cp2Mo2(CO)6+spatula.jpg
| IUPACName = bis(tricarbonyl[η5-cyclopentadienyl]
| OtherNames = cyclopentadienyl molybdenum
carbonyl dimer
Bis(tricarbonylcyclopentadienylmolybdenum)
|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 12091-64-4
| PubChem = 11113722
| ChemSpiderID = 21241602
| EINECS = 235-156-0
| StdInChI=1S/2C5H5.6CO.2Mo/c2*1-2-4-5-3-1;6*1-2;;/h2*1-5H;;;;;;;;
| StdInChIKey = XCUPBPUEWLTPMQ-UHFFFAOYSA-N
| SMILES = [C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].C1=C[CH]C=C1.C1=C[CH]C=C1.[Mo].[Mo]
}}
|Section2={{Chembox Properties
| Formula = Mo2(η-C5H5)2(CO)6
| C=16 | H=10 | O=6 | Mo=2
| Appearance = dark red crystalline solid
| Solubility = insoluble
| Solvent = other solvents
| SolubleOther =
| MeltingPtC = 222
| BoilingPt = dec.
}}
|Section3={{Chembox Structure
| Coordination =
| CrystalStruct = monoclinic
| Dipole = 0.112 D
}}
|Section7={{Chembox Hazards
| ExternalSDS =
| MainHazards = flammable
| FlashPt =
| GHSPictograms = {{GHS06}}{{GHS07}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|302|312|332}}
| PPhrases = {{P-phrases|}}
}}
|Section8={{Chembox Related
| OtherFunction_label = compounds
| OtherFunction = (η-C5H5)2Mo2(CO)4
}}
}}
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 known practical uses.
Structure and synthesis
The molecule exists in two rotamers, gauche and anti.{{cite web | author = Brian Mann | url = http://brian-mann.staff.shef.ac.uk/Cp2Mo2CO6.html | title = Fluxionality of Cp2Mo2(CO)6 | publisher = University of Sheffield |date=1997-01-06}} The six CO ligands are terminal and the Mo-Mo bond distance is 3.2325 Å.{{cite journal | author = R. D. Adams, D. M. Collins, and F. A. Cotton | title = Molecular Structures and Barriers to Internal Rotation in Bis(η5-cyclopentadienyl)hexacarbonylditungsten and Its Molybdenum Analog | journal = Inorg. Chem. | year = 1974 | volume = 13 | pages = 1086–1090 | doi = 10.1021/ic50135a015 | issue = 5| doi-access = free }} The compound is prepared by treatment of molybdenum hexacarbonyl with sodium cyclopentadienide followed by oxidation of the resulting NaMo(CO)3(C5H5).{{cite journal |first1=A. R.|last1= Manning|first2=Paul|last2=Hacket |first3=Ralph|last3=Birdwhistell| year = 1990 | title = Hexacarbonylbis(η5-Cyclopentadienyl)Dichromium, Molybdenum, and Tungsten and their Analogs, M2(η5-C5H4R)2(CO)6 (M = Cr, Mo, and W; R = H, Me or PhCH2) | journal = Inorganic Syntheses | volume = 28 | pages = 148–149 | doi = 10.1002/9780470132593.ch39|isbn= 9780470132593}} Other methods have been developed starting with Mo(CO)3(CH3CN)3 instead of Mo(CO)6.{{cite book |first1=M. David|last1= Curtis |first2=Michael S.|last2=Hay |title= Inorganic Syntheses | year = 1990 | chapter = Cyclopentadienyl Metal Carbonyl Dimers of Molybdenum and Tungsten | series = Inorganic Syntheses | volume = 28 | pages = 150–152 | doi = 10.1002/9780470132593.ch40 |isbn= 9780470132593 }}
Reactions
Thermolysis of this compound in hot solution of diglyme (bis(2-methoxyethyl)ether) results in decarbonylation, giving the tetracarbonyl, which has a formal triple bond between the Mo centers (dMoMo = 2.448 Å):Cotton, F. A.; Walton, R. A. "Multiple Bonds Between Metal Atoms" Oxford (Oxford): 1993, p 564ff. {{ISBN|0-19-855649-7}}.
:(C5H5)2Mo2(CO)6 → (C5H5)2Mo2(CO)4 + 2 CO
The resulting cyclopentadienylmolybdenum dicarbonyl dimer in turn binds a variety of substrates across the metal-metal triple bond.
Related compounds
References
{{molybdenum compounds}}
{{Cyclopentadienide complexes}}
Category:Organomolybdenum compounds
Category:Half sandwich compounds