Lead(IV) acetate

Lead(IV) acetate

Names
IUPAC name Lead(IV) acetate
Systematic IUPAC name Tetrakis(acetyloxy)plumbane
Other names Lead tetraacetate Plumbic acetate
Identifiers
CAS Number	546-67-8  Y
3D model (JSmol)	monodentate acetate: Interactive image bidentate acetate: Interactive image
ChEBI	CHEBI:77245  Y
ChemSpider	10608816
ECHA InfoCard	100.008.099
EC Number	208-908-0
PubChem CID	11025
UNII	CFN24B03DB  Y
CompTox Dashboard (EPA)	DTXSID801047756 DTXSID6041058, DTXSID801047756
InChI InChI=1S/4C2H4O2.Pb/c4*1-2(3)4;/h4*1H3,(H,3,4);/q;;;;+4/p-4 N Key: JEHCHYAKAXDFKV-UHFFFAOYSA-J N
SMILES monodentate acetate:CC(=O)O[Pb](OC(C)=O)(OC(C)=O)OC(C)=O bidentate acetate:O0[C-](C)O[Pb+4]0123(O[C-](C)O1)(O[C-]C(C)O2)O[C-](C)O3
Properties
Chemical formula	(CH3CO2)4Pb
Molar mass	443.376 g/mol
Appearance	colorless or pink columnar crystals
Odor	vinegar
Density	2.228 g/cm3 (17 °C)
Melting point	175 °C (347 °F; 448 K)
Boiling point	decomposes
Solubility in water	soluble, reversible hydrolysis
Solubility	Reacts with ethanol. Soluble in chloroform, benzene, nitrobenzene, hot acetic acid, HCl(aq), tetrachloroethane.
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Toxic
GHS labelling: [1]
Pictograms
Signal word	Danger
NFPA 704 (fire diamond)	3 0 0
Related compounds
Related compounds	Lead(II) acetate Tin(IV) acetate Zirconium(IV) acetate Bismuth(III) acetate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N  verify  (what is  YN ?) Infobox references

Lead(IV) acetate or lead tetraacetate is an metalorganic compound with chemical formula (CH₃CO₂)₄Pb, often abbreviated as Pb(OAc)₄, where Ac is acetyl. It is a colorless solid that is soluble in nonpolar, organic solvents, indicating that it is not a salt. It is degraded by moisture and is typically stored with additional acetic acid. The compound is used in organic synthesis. ^[2]

Structure

In the solid state the lead(IV) centers are coordinated by four acetate ions, which are bidentate, each coordinating via two oxygen atoms. The lead atom is 8 coordinate and the O atoms form a flattened trigonal dodecahedron. ^[3]

Preparation

It is typically prepared by treating of red lead with acetic acid and acetic anhydride (Ac₂O), which absorbs water. The net reaction is shown: ^{[4] [5]}

Pb₃O₄ + 4 Ac₂O → Pb(OAc)₄ + 2 Pb(OAc)₂

The remaining lead(II) acetate can be partially oxidized to the tetraacetate by Cl₂, with a PbCl₂ by-product:

2 Pb(OAc)₂ + Cl₂ → Pb(OAc)₄ + PbCl₂

Reagent in organic chemistry

Lead tetraacetate is a strong oxidizing agent, ^[6] a source of acetyloxy groups, and a general reagent for the preparation of organolead compounds. Some of its many uses in organic chemistry:

• Acetoxylation of benzylic, allylic, ^[7] and α-oxygen ether C−H bonds, for example the conversion of dioxane to 2-acetoxy-1,4-dioxane ^[8]
• An alternative reagent to bromine in Hofmann rearrangement ^[9]
• Dehydrogenation of hydrazones and hydrazines, for example that of hexafluoroacetone hydrazone to bis(trifluoromethyl)diazomethane ^{[10] [11]}
• Cleavage of α-hydroxy acids ^[12] or 1,2-diols to their corresponding aldehydes or ketones, often replacing ozonolysis; for instance, the oxidation of di-n-butyl D-tartrate to n-butyl glyoxylate. ^[13]
• Reaction with alkenes to form γ-lactones
• Oxidation of alcohols carrying a δ-proton to cyclic ethers. ^[14]
• Oxidative cleavage of certain allyl alcohols in conjunction with ozone: ^{[15] [16]}
• Transformation of 1,2-dicarboxylic acids or cyclic anhydrides to alkenes

oxidative cleavage of allyl alcohols

• Conversion of acetophenones to phenyl acetic acids ^[17]
• Decarboxylation of carboxylic acids to alkyl halides in the Kochi reaction ^[18]

Safety

Lead(IV) acetate is toxic, because of lead. It is a neurotoxin. It badly affects the gum tissue, central nervous system, kidneys, blood, and reproductive system.

References

1. "Substance Information - ECHA". echa.europa.eu.
2. Mihailo Lj. Mihailović; Živorad Čeković; Brian M. Mathes (2005). "Lead(IV) Acetate". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rl006.pub2. ISBN   978-0-471-93623-7.
3. Schürmann, M.; Huber, F. (1994). "A redetermination of lead(IV) acetate". Acta Crystallographica Section C. 50 (11): 1710–1713. doi:10.1107/S0108270194006438. ISSN   0108-2701.
4. J. C. Bailar, Jr. (1939). "Lead Tetracetate". Inorganic Syntheses. Inorganic Syntheses. Vol. 1. pp. 47–49. doi:10.1002/9780470132326.ch17. ISBN   978-0-470-13232-6.
5. M. Baudler (1963). "Lead(IV) Acetate". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2. NY, NY: Academic Press. p. 767.
6. J. Zýka (1966). "Analytical study of the basic properties of lead tetraacetate as oxidizing agent" (PDF). Pure and Applied Chemistry. 13 (4): 569–581. doi:10.1351/pac196613040569. S2CID   96821219 . Retrieved 19 December 2013.
7. "(1R,5R)-(+)-Verbenone of High Optical Purity". Organic Syntheses. 72: 57. 1995. doi:10.15227/orgsyn.072.0057.
8. Organic Syntheses, Vol. 82, p. 99 (2005) Article.
9. Baumgarten, Henry; Smith, Howard; Staklis, Andris (1975). "Reactions of amines. XVIII. Oxidative rearrangement of amides with lead tetraacetate". The Journal of Organic Chemistry. 40 (24): 3554–3561. doi:10.1021/jo00912a019.
10. Middleton, W. J.; Gale, D. M. (1970). "Bis(Trifluoromethyl)Diazomethane". Organic Syntheses. 50: 6. doi:10.15227/orgsyn.050.0006.
11. Robert K. Muller, Renato Joos, Dorothee Felix, Jakob Schreiber, Claude Wintner, and A. Eschenmoser (1976). "Preparation of N-Aminoaziridines: trans-1-Amino-2,3-diphenylaziridine, 1-Amino-2-phenylaziridine, and 1-Amino-2-phenylaziridinium Acetate". Organic Syntheses. 55: 114. doi:10.15227/orgsyn.055.0114.
12. Ōeda, Haruomi (1934). "Oxidation of some α-hydroxy-acids with lead tetraacetate". Bulletin of the Chemical Society of Japan. 9 (1): 8–14. doi: 10.1246/bcsj.9.8 .
13. Organic Syntheses, Coll. Vol. 4, p. 124 (1963); Vol. 35, p. 18 (1955) Article.
14. M B Smith, J March. March's Advanced Organic Chemistry (Wiley, 2001) ( ISBN   0-471-58589-0)
15. Álvarez Manzaneda, E. J.; Chahboun, R.; Cano, M. J.; Cabrera Torres, E.; Álvarez, E.; Álvarez Manzaneda, R.; Haidour, A.; Ramos López, J. M. (2006). "O₃/Pb(OAc)₄: a new and efficient system for the oxidative cleavage of allyl alcohols". Tetrahedron Letters . 47 (37): 6619–6622. doi:10.1016/j.tetlet.2006.07.020.
16. Conversion of 1-allylcyclohexanol to cyclohexanone, in the proposed reaction mechanism the allyl group is first converted to a trioxalane according to conventional ozonolysis which then interacts with the alkoxy lead group.
17. Myrboh, B.; Ila, H.; Junjappa, H. (1981). "One-Step Synthesis of Methyl Arylacetates from Acetophenones Using Lead(IV) Acetate". Synthesis . 2 (2): 126–127. doi:10.1055/s-1981-29358.
18. Jay K. Kochi (1965). "A New Method for Halodecarboxylation of Acids Using Lead(IV) Acetate". J. Am. Chem. Soc. 87 (11): 2500–02. doi:10.1021/ja01089a041.