Hafnocene dichloride

Hafnocene dichloride
Names
Other names
bis(cyclopentadienyl)hafnium dichloride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.031.967 Edit this at Wikidata
EC Number
  • 235-177-5
  • InChI=1S/2C5H5.2ClH.Hf/c2*1-2-4-5-3-1;;;/h2*1-3H,4H2;2*1H;/q2*-1;;;+4/p-2
    Key: IXKLRFLZVHXNCF-UHFFFAOYSA-L
  • C1C=CC=[C-]1.C1C=CC=[C-]1.[Cl-].[Cl-].[Hf+4]
Properties
C10H10Cl2Hf
Molar mass 379.58 g·mol−1
Appearance white solid
Melting point 230–233 °C (446–451 °F; 503–506 K)
Hazards
GHS labelling:[1]
GHS05: CorrosiveGHS07: Exclamation mark
Danger
H314, H315, H319, H335
P260, P261, P264, P264+P265, P271, P280, P301+P330+P331, P302+P352, P302+P361+P354, P304+P340, P305+P351+P338, P305+P354+P338, P316, P319, P321, P332+P317, P337+P317, P362+P364, P363, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Hafnocene dichloride is the organohafnium compound with the formula (C5H5)2HfCl2. It is a white solid that is sparingly soluble in some organic solvents. The lighter homologues zirconacene dichloride and titanocene dichloride have received much more attention. While hafnocene is only of academic interest, some more soluble derivatives are precatalysts for olefin polymerization. Moreso than the Zr analogue, this compound is highly resistant to reduction.

It is prepared by a salt metathesis reaction from hafnium tetrachloride by salt metathesis:

2 NaC5H5 + HfCl4 → (C5H5)2HfCl2 + 2 NaCl

Derivatives

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Hydrolysis gives the trimer [(C5H5)2HfO]3.[2]

The chloride ligands can be replaced by other halides.[3]

The bis(phosphide) (C5H5)2Hf(PR2)2 can be prepared by salt metathesis from hafnocene dichloride.[4]

References

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  1. ^ "Hafnocene dichloride". pubchem.ncbi.nlm.nih.gov.
  2. ^ Rogers, Robin D.; Vann Bynum, R.; Atwood, Jerry L. (1982). "Synthesis and Crystal Structure of [(η5-C5H5)2HfO]3C6H5Me". Journal of Crystallographic and Spectroscopic Research. 12 (3): 239–244. doi:10.1007/BF01195715. S2CID 97164127.
  3. ^ Druce, P. M.; Kingston, B. M.; Lappert, M. F.; Spalding, T. R.; Srivastava, R. C. (1969). "Metallocene Halides. Part I. Synthesis, Spectra, and Redistribution Equilibria of di-π-Cyclopentadienyldihalogeno-Titanium(IV),-Zirconium-(IV), and -Hafnium(IV)". J. Chem. Soc. A: 2106–2110. doi:10.1039/J19690002106.
  4. ^ Baker, R. T.; Whitney, J. F.; Wreford, S. S. (1983). "Characterization and Interconversion of Metal-Phosphorus Single and Double bonds: Bis(cyclopentadienyl)zirconium and -Hafnium Bis(diorganophosphide) Complexes". Organometallics. 2 (8): 1049–1051. doi:10.1021/om50002a022.