Vanadyl acetylacetonate

Vanadyl acetylacetonate

Chembox new
ImageFile = Vanadyl-acetylacetonate-from-xtal-3D-balls.png ImageSize =
IUPACName =
OtherNames = VO(acac)2
Section1 = Chembox Identifiers
CASNo = 3153-26-2
PubChem = 24880742
SMILES =
Section2 = Chembox Properties
Formula = C10H14O5V
MolarMass = 265.16
Appearance = blue-green
Density =
MeltingPt = 256-259 °C (dec.)
BoilingPt =
Solubility = CHCl3, CH2Cl2, Benzene
Section3 = Chembox Hazards
MainHazards =
FlashPt =
Autoignition =

Vanadyl(acetylacetonate) is the chemical compound with the formula VO(C5H7O2)2. This blue-green coordination complex consists of the vanadyl group, VO2+, bound to two acetylacetonate anions, acac−. Like other charge-neutral acetylacetonates, this complex is soluble in organic solvents.

ynthesis

The complex is prepared from vanadium(IV) or vanadium(V) precursors, the latter being more convenient:Richard A. Rowe, Mark M. Jones, Burl E. Bryant, W. Conard Fernelius "Vanadium(IV) Oxy(acetylacetonate)" Inorganic Syntheses, 1957, volume 5, pp. 113-116.] :2 V2O5 + 9 C5H8O2 → 4 VO(C5H7O2)2 + (CH3CO)2O + 5 H2O

tructure 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.

Applications

It is used in organic chemistry as a reagent in the epoxidation of allylic alcohols in combination with tert-butyl hydroperoxide (TBHP). The VO(acac)2-TBHP system exclusively epoxidizes geraniol at the allylic alcohol position. For comparison, another epoxidizing agent m-CPBA, reacts exclusively with the other alkene group. TBHP oxidizes VO(acac)2 to a vanadium(V) species which coordinates the alcohol of the substrate and the hydroperoxide. [cite journal | author = Takashi Itoh, Koichiro Jitsukawa, Kiyotomi Kaneda, Shiichiro Teranishi | title = Vanadium-catalyzed epoxidation of cyclic allylic alcohols. Stereoselectivity and stereocontrol mechanism | journal = J. Am. Chem. Soc. | year = 1979 | volume = 101 | issue = 1 | pages = 159–169 | doi = 10.1021/ja00495a027]

Biomedical aspects

Vanadyl(acac) exhibits insulin mimetic properties, in that in can stimulate the phosphorylation of protein kinase B (PKB/Akt) and glycogen synthase kinase-3 (GSK3)cite journal | author = Mohamad Z. Mehdi and Ashok K. Srivastava | title = Organo-vanadium compounds are potent activators of the protein kinase B signaling pathway and protein tyrosine phosphorylation: Mechanism of insulinomimesis | journal = ABB | year = 2005 | volume = 440 | pages = 158–164 | doi = 10.1016/j.abb.2005.06.008] . It has also been shown inhibit tyrosine phosphatase(PTPase), PTPases such as PTP1B, which dephosphorylates insulin receptor beta subunit, thus increasing its phosphorylation, allowing for a prolonged activation of IRS-1, PKB, and GSK3, allowing them to exert their anti-diabetic properties.

External links

* [http://www-oc.chemie.uni-regensburg.de/OCP/ch/chb/oc5/Oxidation_reactions-08.pdf Oxidations tutorial]

References


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