Vanadyl acetylacetonate

Vanadyl acetylacetonate is the chemical compound with the formula VO(acac)₂, where acac^– is the conjugate base of acetylacetone. It is a blue-green solid that dissolves in polar organic solvents. The coordination complex consists of the vanadyl group, VO²⁺, bound to two acac^– ligands via the two oxygen atoms on each. Like other charge-neutral acetylacetonate complexes, it is not soluble in water.

Vanadyl acetylacetonate

Names
IUPAC name oxobis(2,4-pentanedionato)vanadium(IV)
Other names VO(acac)2, VO(pd)2
Identifiers
CAS Number	3153-26-2 Y
3D model (JSmol)	Interactive image
ChemSpider	17344686
ECHA InfoCard	100.019.628
EC Number	221-590-8
PubChem CID	16217092
CompTox Dashboard (EPA)	DTXSID70904369
SMILES CC(=[O+]1)C=C(C)O[V-3]12(#[O+])OC(C)=CC(C)=[O+]2
Properties
Chemical formula	C10H14O5V
Molar mass	265.157 g/mol
Appearance	blue-green
Density	1.50 g/cm3
Melting point	258 °C (496 °F; 531 K)
Boiling point	174 °C (345 °F; 447 K) at 0.2 torrs (27 Pa)
Solubility in water	CHCl3, CH2Cl2, Benzene, CH3OH, CH3CH2OH
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Synthesis

The complex is generally prepared from vanadium(IV), e.g. vanadyl sulfate:^[1]

VOSO₄ + 2 Hacac → VO(acac)₂ + H₂SO₄

It can also be prepared by a redox reaction starting with vanadium pentoxide. In this reaction, some acetylacetone is oxidized to 2,3,4-Pentanetrione.^[1]

Structure and properties

The complex has a square pyramidal structure with a short V=O bond. This d¹ compound is paramagnetic. Its optical spectrum exhibits two transitions. It is a weak Lewis acid, forming adducts with pyridine and methylamine.^[1]

Applications

It is used in organic chemistry as a catalyst for the epoxidation of allylic alcohols by tert-butyl hydroperoxide (TBHP). The VO(acac)₂–TBHP system exclusively epoxidizes geraniol at the allylic alcohol position, leaving the other alkene of geraniol untouched. By comparison, m-CPBA, another epoxidizing agent, reacts with both alkenes, creating the products in a two to one ratio favoring reaction at the alkene away from the hydroxyl group. TBHP oxidizes VO(acac)₂ to a vanadium(V) species which coordinates the alcohol of the substrate and the hydroperoxide, directing the epoxidation to occur at the alkene close to this coordination site.^[2][3]

Biomedical aspects

Vanadyl acetylacetonate exhibits insulin mimetic properties, in that it can stimulate the phosphorylation of protein kinase B (PKB/Akt) and glycogen synthase kinase 3 (GSK-3).^[4] It has also been shown inhibit tyrosine phosphatase (PTPase), PTPases^{[clarification needed]} such as PTP1B, which dephosphorylates insulin receptor beta subunit, thus increasing its^{[clarification needed]} phosphorylation, allowing for a prolonged activation of IRS-1, PKB, and GSK-3, allowing them to exert their anti-diabetic properties.^[4]

External links

• Oxidations tutorial