Molybdocene dichloride

Molybdocene dichloride

Names
IUPAC name dichlorobis(η^5-cyclopentadienyl)molybdenum(IV)
Other names molybdocene dichloride, molybdenocene dichloride, dichloridobis(cyclopentadienyl)molybdenum(IV)
Identifiers
CAS Number	12184-22-4
ChemSpider	398274
Jmol interactive 3D	Image
PubChem	452153
InChI InChI=1S/2C5H5.2ClH.Mo/c2*1-2-4-5-3-1;;;/h2*1-5H;2*1H;/q2*-1;;;+2/p-2 Key: QGGWSCVAFKWITK-UHFFFAOYSA-L InChI=1/2C5H5.2ClH.Mo/c2*1-2-4-5-3-1;;;/h2*1-5H;2*1H;/q2*-1;;;+2/p-2/r2C5H5.Cl2Mo/c2*1-2-4-5-3-1;1-3-2/h2*1-5H;/q2*-1; Key: QGGWSCVAFKWITK-OWLYHJECAX
SMILES [cH-]1cccc1.[cH-]1cccc1.Cl[Mo]Cl
Properties
Chemical formula	C10H10Cl2Mo
Molar mass	297.04 g·mol^−1
Appearance	greenish-brown powder
Solubility in water	insoluble, moisture sensitive
Hazards
Safety data sheet	[1]
Related compounds
Related compounds	Ferrocene Zirconocene dichloride Vanadocene dichloride Niobocene dichloride Titanocene dichloride Tantalocene dichloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Molybdocene dichloride is the organomolybdenum compound with the formula (η⁵-C₅H₅)₂MoCl₂ and IUPAC name dichlorobis(η⁵-cyclopentadienyl)molybdenum(IV), and is commonly abbreviated as Cp₂MoCl₂. It is a brownish-green air- and moisture-sensitive powder. In the research laboratory, it is used to prepare many derivatives.

Preparation and structure

The compound was first reported in 1964 by Malcolm Green and his student Cooper.^[2] It is prepared from molybdocene dihydride, which in turn is prepared by a famously complex reaction involving molybdenum pentachloride, sodium cyclopentadienide, and sodium borohydride. The dihydride converts to the dichloride upon treatment with chloroform:^[3]

(C₅H₅)₂MoH₂ + 2 CHCl₃ → (C₅H₅)₂MoCl₂ + 2 CH₂Cl₂

The compound adopts a "clamshell" structure where the Cp rings are not parallel, the average Cp(centroid)-M-Cp angle being 130.6°. The two chloride ligands are cis, the Cl-Mo-Cl angle of 82° being narrower than in niobocene dichloride (85.6°), which in turn is less than in zirconacene dichloride (92.1°). This trend helped to establish the orientation of the HOMO in this class of complex.^[4]

Uses

Unlike the titanocene and zirconacene derivatives, the molybddocene compounds have yielded no commercial applications.

All metallocene dihalides exhibit some anti-cancer activity,^[5] but these have not yielded useful compounds in the clinic.^[6]

References

1. "42-0100 Molybdenum " Bis(cyclopentadienyl)molybdenum dichloride, 99%". Strem Chemicals. 27 July 2011. Retrieved 5 February 2012.
2. R. L. Cooper and M. L. H. Green, Z. Naturforsch., B: Anorg. Chem. Org. Chem. 1964, volume 19, pp. 652. R. L. Cooper and M. L. H. Green, J. Chem. Soc. (A), 1967, p. 1155.
3. Silavwe, Ned D.; Castellani, Michael P.; Tyler, David R. (1992). "Bis(η5-Cyclopentadienyl)Molybdenum(IV) Complexes". Inorganic Syntheses 29: 204–211. doi:10.1002/9780470132609.ch50.
4. K. Prout, T. S. Cameron, R. A. Forder, and in parts S. R. Critchley, B. Denton and G. V. Rees "The crystal and molecular structures of bent bis-π-cyclopentadienyl-metal complexes: (a) bis-π-cyclopentadienyldibromorhenium(V) tetrafluoroborate, (b) bis-π-cyclopentadienyldichloromolybdenum(IV), (c) bis-π-cyclopentadienylhydroxomethylaminomolybdenum(IV) hexafluorophosphate, (d) bis-π-cyclopentadienylethylchloromolybdenum(IV), (e) bis-π-cyclopentadienyldichloroniobium(IV), (f) bis-π-cyclopentadienyldichloromolybdenum(V) tetrafluoroborate, (g) μ-oxo-bis[bis-π-cyclopentadienylchloroniobium(IV)] tetrafluoroborate, (h) bis-π-cyclopentadienyldichlorozirconium" Acta Crystallogr. 1974, volume B30, pp. 2290–2304. doi:10.1107/S0567740874007011
5. Roat-Malone, R. M. (2007). Bioinorganic Chemistry: A Short Course (2nd ed.). John Wiley & Sons. pp. 19–20. ISBN 978-0-471-76113-6.
6. Waern, J. B.; Dillon, C. T.; Harding, M. M. (2005). "Organometallic Anticancer Agents:  Cellular Uptake and Cytotoxicity Studies on Thiol Derivatives of the Antitumor Agent Molybdocene Dichloride". J. Med. Chem. 48 (6): 2093–2099. doi:10.1021/jm049585o.