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Niobocene dichloride

Niobocene dichloride

General
Systematic name	Dichlorobis(η5-cyclopentadienyl)- niobium(IV)
Other names	Niobocene dichloride
Molecular formula	C₁₀H_1oCl₂Nb
Molar mass	294 g/mol
Appearance	brown solid
CAS number	[12793-14-5]
Properties
Density and phase
Solubility in water	insoluble
Other solvents	sparingly in chlorocarbons
Melting point
Boiling point	dec.
R/S statement	R: 36/37/38 S: 26-36
RTECS	QU0400000
Related compounds	Cp₂TiCl₂ Cp₂MoCl₂ Cp₂VCl₂
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Niobocene dichloride, formally dichlorobis(η5-Cyclopentadienyl)niobium(IV), is the chemical compound with the formula (C₅H₅)₂NbCl₂ or Cp₂NbCl₂. This paramagnetic brown solid is a useful starting reagent. It is being investigated as an anti-cancer agent.^[1]

Additional recommended knowledge

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The compound is a pseudotetrahedral with two cyclopentadienyl and two chloro substituents attached to the metal. A variety of similar compounds are known, including Cp₂TiCl₂.

It is prepared via a multistep reaction beginning with reductive alkylation of niobium pentachloride with cyclopentadienylsodium:^[2]

NbCl₅ + 6 NaC₅H₅ → 5 NaCl + (C₅H₅)₄Nb + organic products

(C₅H₅)₄Nb + 2 HCl + 0.5 O₂) → [{C₅H₅)₂NbCl}₂O]Cl₂ + 2 C₅H₆

2 HCl + [{(C₅H₅)₂NbCl}₂O]Cl₂ + SnCl₂ → 2 (C₅H₅)2NbCl₂ + SnCl₄ + H₂O

References

^ Mokdsi, G.; Harding, M. M. (2001). "A ¹H NMR study of the Interaction of Antitumor Metallocenes with Glutathione". Journal of Inorganic Biochemistry 86: 611-616.
^ C. R. Lucas, J. A. Labinger, J. Schwartz (1990). "Dichlorobis(η5-Cyclopentadienyl)Niobium(IV)". Inorganic Syntheses 28: 267-270. doi:10.1002/9780470132593.ch68.