Vanadyl acetylacetonate
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| Names | |
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| IUPAC name
oxobis(2,4-pentanedionato)vanadium(IV)
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| Other names
VO(acac)2, VO(pd)2
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| Identifiers | |
3153-26-2  |
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| PubChem | 16217092 |
| Properties | |
| 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) |
| CHCl3, CH2Cl2, Benzene, CH3OH, CH3CH2OH | |
| Vapor pressure | {{{value}}} |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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| Infobox references | |
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.
Contents
Synthesis
The complex is prepared from vanadium(IV), e.g. vanadyl sulfate, or vanadium(V) precursors, such as vanadium pentoxide.[1] The equation for the redox reaction starting from the pentoxide can be described by this approximate equation:
- 2 V2O5 + 9 C5H8O2 → 4 VO(C5H7O2)2 + (CH3CO)2CO + 5 H2O
The compound is recrystallized from chloroform.
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 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 with both groups, creating the products in a two to one ratio, favoring the allylic position away from the alcohol. TBHP oxidizes VO(acac)2 to a vanadium(V) species which coordinates the alcohol of the substrate and the hydroperoxide.[2][3]
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).[4] 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.[4]
