Organovanadium chemistry

Organovanadium chemistry is the chemistry of organometallic compounds containing a carbon (C) to vanadium (V) chemical bond.[1] Organovanadium compounds find only minor use as reagents in organic synthesis but are significant for polymer chemistry as catalysts.[2]

Oxidation states for vanadium are +2, +3, +4 and +5. Low valency vanadium is usually stabilized with carbonyl ligands. Oxo derivatives are relatively common, unlike the organic complexes of neighboring elements.

## Contents

* 1 Compound classes
* 1.1 Carbonyls
* 1.2 Cyclopentadienyl derivatives
* 1.3 Arene complexes
* 1.4 Alkyl and aryl derivatives
* 2 Catalysts and reagents
* 3 References

## Compound classes

### Carbonyls

Vanadium carbonyl can be prepared by reductive carbonylation of vanadium salts:

4 Na + VCl3 \+ 6 CO → Na[V(CO)6] + 3 NaCl

The salt can be oxidized to the 17e binary carbonyl V(CO)6.

### Cyclopentadienyl derivatives

thumb|right|130px|(Cycloheptatrienyl)(cyclopentadienyl)vanadium is one of many organovanadium compounds that is paramagnetic. Vanadocene dichloride, the first organovanadium complexes to be reported,[3] is prepared from sodium cyclopentadienyl and vanadium tetrachloride:

2 NaC5H5 \+ VCl4 → VCp2Cl2 \+ 2NaCl

Reduction of this compound gives the parent vanadocene (Cp2V):

VCp2Cl2 \+ LiAlH4 → VCp2

Cp2V2(CO)5 featuring a pair of semi-bridging CO ligands.[4]

Vanadocene is the lightest transition metal metallocene that is isolable at room temperature.[5] Vanadocene reacts with high pressures of carbon monoxide to give CpV(CO)4.[6] Photolysis of the tetracarbonyl gives Cp2V2(CO)5. Several analogous indenyl complexes are known.

Monocyclopentadienyl vanadium chlorides include CpVCl3 and the diamagnetic CpVOCl2.

### Arene complexes

Vanadium forms a variety of arene complexes, e.g. with benzene:

VCl4 \+ Al + 2 C6H6 → [V(η6-C6H6)2]AlCl4
[V(η6-C6H6)2]AlCl4 \+ H2O → V(η6-C6H6)2 \+ ...

### Alkyl and aryl derivatives

A handful of alkyl and aryl complexes exist. The reactive species V(mesityl)3 forms from VCl3:[7]

VCl3(THF)3 \+ 3 LiC6H2-2,4,6-Me3 → V(C6H2-2,4,6-Me3)3(THF) + 3 LiCl

This species binds CO and, under appropriate conditions, N2. V(mesityl)3 adds a fourth mesityl group and the resulting "ate complex" can be oxidized to the vanadium(IV) derivative:

V(mes)3(THF) + LiMes → Li[V(mes)4]
Li[V(mes)4] + air → V(mes)4(THF)

The tetrakis(norbornyl) complex is also known.

Vanadium oxytrichloride is a starting material for organovanadium(IV) and organovanadium(V) compounds:

VOCl3 \+ Li(mes) → Li[VO(mes)3]
Li[VO(mes)3] + chloranil → VO(mes)3
VOCl3 \+ ZnPh2 → VOPhCl2 \+ "ZnPh(Cl)"

## Catalysts and reagents

Well-defined vanadium compounds do not appear as catalysts in any commercial process.[8] However organovanadium species are clearly implicated as catalysts for the production of butadiene-based rubbers. These catalysts are generated in situ by treating soluble coordination complexes such as vanadium(III) acetylacetonate with organoaluminium activators.[9][10]

## References

1. ↑ Synthesis of Organometallic Compounds: A Practical Guide Sanshiro Komiya Ed. 1997
2. ↑ Kotohiro Nomura; Shu Zhang (2011). "Design of Vanadium Complex Catalysts for Precise Olefin Polymerization". Chem. Rev. 111 (3): 2342–2362. doi:10.1021/cr100207h. PMID 21033737.
3. ↑ Wilkinson, G.; Birmingham, J. G. (1954). "Bis-cyclopentadienyl Compounds of Ti, Zr, V, Nb and Ta". Journal of the American Chemical Society 76 (17): 4281–4284. doi:10.1021/ja01646a008.
4. ↑ Fischer, Ernst Otto; Schneider, Robert J. J. (1970). "Über Aromatenkomplexe von Metallen, CXIV. Darstellung und Reaktionen von Dicyclopentadienyl‐divanadin‐pentacarbonyl, (C 5 H 5 ) 2 V 2 (CO) 5". Chemische Berichte 103 (11): 3684–3695. doi:10.1002/cber.19701031133.
5. ↑ Robert Choukroun, Christian Lorber (2005). "Adventures in Vanadocene Chemistry". Eur. J. Inorg. Chem. 2005 (23): 4683–4692. doi:10.1002/ejic.200500371.
6. ↑ King, R.B.; Stone, F.G.A (1963). "Cyclopentadienyl Metal Carbonyls and Some Derivatives". Inorganic Syntheses. 7. 99–115. doi:10.1002/9780470132388.ch31. ISBN 978-0-470-13238-8.
7. ↑ Vivanco, M.; Ruiz, J.; Floriani, C.; Chiesi-Villa, A.; Rizzoli, C. "Chemistry of the vanadium-carbon .sigma. bond. 1. Insertion of carbon monoxide, isocyanides, carbon dioxide, and heterocumulenes into the V-C bond of Tris(mesityl)vanadium(III)" Organometallics 1993 volume 12, 1794–1801. doi:10.1021/om00029a042
8. ↑ Toshikazu Hirao (1997). "Vanadium in Modern Organic Synthesis". Chemical Reviews 97 (8): 2707–2724. doi:10.1021/cr960014g. PMID 11851478.
9. ↑ Kotohiro Nomura; Shu Zhang (2011). "Design of Vanadium Complex Catalysts for Precise Olefin Polymerization". Chem. Rev. 111 (3): 2342–2362. doi:10.1021/cr100207h. PMID 21033737.
10. ↑ Werner Obrecht; Jean-Pierre Lambert; Michael Happ; Christiane Oppenheimer-Stix; John Dunn; Ralf Krüger (2012). "Ullmann's Encyclopedia of Industrial Chemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.o23_o01.

* v
* t
* e

Compounds of carbon with other elements in the periodic table

| CH |  |  |  | He

|
|
|
|

CLi | CBe | CB | CC | CN | CO | CF | Ne
CNa | CMg | CAl | CSi | CP | CS | CCl | CAr
CK | CCa | CSc |  | CTi | CV | CCr | CMn | CFe | CCo | CNi | CCu | CZn | CGa | CGe | CAs | CSe | CBr | CKr
CRb | CSr | CY |  | CZr | CNb | CMo | CTc | CRu | CRh | CPd | CAg | CCd | CIn | CSn | CSb | CTe | CI | CXe
CCs | CBa | CLa |  | CHf | CTa | CW | CRe | COs | CIr | CPt | CAu | CHg | CTl | CPb | CBi | CPo  | CAt  | Rn
Fr  | CRa | Ac |  | Rf  | Db  | CSg  | Bh  | Hs  | Mt  | Ds  | Rg  | Cn  | Nh  | Fl  | Mc  | Lv  | Ts  | Og
|  | CCe | CPr | CNd | CPm | CSm | CEu | CGd | CTb | CDy | CHo | CEr | CTm | CYb | CLu
|  | CTh | CPa | CU | CNp | CPu | CAm | CCm | CBk | CCf | CEs | Fm | Md | No | Lr

Legend|

* Chemical bonds to carbon
* Core organic chemistry
* Many uses in chemistry
* Academic research, no widespread use
* Bond unknown

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