Hexafluoroacetylacetone

Hexafluoroacetylacetone is the chemical compound with the nominal formula CF3C(O)CH2C(O)CF3 (often abbreviated as hfacH). This colourless liquid is a ligand precursor and a reagent used in MOCVD. The compound exists exclusively as the enol CF3C(OH)=CHC(O)CF3. For comparison under the same conditions, acetylacetone is 85% enol.[1]

Hexafluoroacetylacetone
Names
IUPAC name
1,1,1,5,5,5-Hexafluoro-2,4-pentanedione
Other names
Hexafluoroacetylacetone, HfacH
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.014.719
Properties
C5H2F6O2
Molar mass 208.06 g/mol
Appearance colourless liquid
Density 1.47 g/mL
Boiling point 70 to 71 °C (158 to 160 °F; 343 to 344 K)
organic solvents
Hazards
Main hazards toxic
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

Metal complexes of the conjugate base exhibit enhanced volatility and Lewis acidity relative to analogous complexes derived from acetylacetone. The visible spectra of bis(hexafluoroacetylacetonato)copper(II) and its dehydrate have been reported in carbon tetrachloride.[2]. Compounds of the type bis(hexafluoroacetylacetonato)copper(II):Bn , where :B are Lewis bases such as N,N-dimethylacetamide, dimethyl sulfoxide, or pyridine and n = 1 or 2, have been prepared. Since bis(hexafliuoroacetylacetonato)copper(II) is soluble in carbon tetrachloride, its Lewis acid properties have been studied for 1:1 adducts using a variety of Lewis bases. .[3] Its Lewis acid properties have been analyzed by the ECW model yielding EA= 1.82 and CA= 2.86. When bis(hexafluoroacetylacetonato)copper(II) forms an adduct with triethylamine, steric repulsion due to ethyl groups on nitrogen results but for Lewis bases such as pyridine and ethyl acetate steric repulsion is not observed.

This organofluorine compound was first prepared by the condensation of ethyl ester of trifluoroacetic acid and 1,1,1-trifluoroacetone.[4] It has been investigated as an etchant for copper and its complexes, such as Cu(Hfac)(trimethylvinylsilane) have been employed as precursors in microelectronics.[5]

Being highly electrophilic, hexafluoroacetylacetone is hydrated in water to give the tetraol.[6]

References

  1. Jane L. Burdett; Max T. Rogers (1964). "Keto-Enol Tautomerism in β-Dicarbonyls Studied by Nuclear Magnetic Resonance Spectroscopy. I. Proton Chemical Shifts and Equilibrium Constants of Pure Compounds". J. Am. Chem. Soc. 86: 2105–2109. doi:10.1021/ja01065a003.
  2. Bertrand, J. A..; Kaplan, R. I. (1965). "A Study of Bis(hexafluoroacetylacetonató)copper(II)". Inorganic Chemistry. 5: 489–491.CS1 maint: uses authors parameter (link)
  3. Partenheimer, W.; Drago, R. S. (1970). "Preparation and Thermodynamic Data for Adducts of Bases with Some Copper(II) 0-Diketonates". Inorganic Chemistry. 9: 47–52.CS1 maint: uses authors parameter (link)
  4. Henne, Albert L.; Newman, Melvin S.; Quill, Laurence L.; Staniforth, Robert A. (1947). "Alkaline condensation of fluorinated esters with esters and ketones". Journal of the American Chemical Society. 69 (7): 1819–20. doi:10.1021/ja01199a075.
  5. Mark J. Hampden-Smith; Toivo T. Kodas (1995). "Chemical vapour deposition of copper from (hfac)CuL compounds". Polyhedron. 14 (6): 699–732. doi:10.1016/0277-5387(94)00401-Y.
  6. Aygen, S.; van Eldik, R. (1989). "A Spectroscopic and Mechanistic Study of the Enolization and Diol Formation of Hexafluoroacetylacetone in the Presence of Water and Alcohol". Chem. Ber. 122 (2): 315. doi:10.1002/cber.19891220218.
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