Tris(acetylacetonato)iron(III)

Tris(acetylacetonato) iron(III), often abbreviated Fe(acac)₃, is a ferric coordination complex featuring acetylacetonate (acac) ligands, making it one of a family of metal acetylacetonates. It is a red air-stable solid that dissolves in nonpolar organic solvents.

Tris(acetylacetonato)iron(III)

Names
IUPAC name Tris(2,4-dioxopentan-3-ido-κ2O,O′)iron
Other names Iron(III) acetylacetonate, Iron(III) tris(2,4-pentanedionato), Fe(acac)3
Identifiers
CAS Number	14024-18-1 Y
3D model (JSmol)	Interactive image
ChemSpider	4588230
ECHA InfoCard	100.034.398
EC Number	237-853-5
PubChem CID	139087805
UNII	118BHF260P Y
CompTox Dashboard (EPA)	DTXSID3051707
InChI InChI=1S/3C5H8O2.Fe/c3*1-4(6)3-5(2)7;/h3*3,6H,1-2H3;/q;;;+3/p-3/b3*4-3-; Key: AQBLLJNPHDIAPN-LNTINUHCSA-K
SMILES CC(=C[C-](C)O1)O[Fe+3]123(OC(=C[C-](C)O2)C)OC(=C[C-](C)O3)C
Properties
Chemical formula	Fe(C5H7O2)3
Molar mass	353.17 g/mol
Appearance	Red Solid
Density	1.348 g/cm3
Melting point	180 to 181 °C (356 to 358 °F; 453 to 454 K)
Boiling point	decomposes
Solubility in water	2 g/L
Hazards
GHS labelling:[1]
Pictograms
Signal word	Danger
Hazard statements	H302+H312+H332, H318
Precautionary statements	P261, P280, P301+P312, P302+P352+P312, P304+P340+P312, P305+P351+P338
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

Infrared spectrum of Tris(acetylacetonato)iron(III)

Preparation

Fe(acac)₃ is prepared by treating freshly precipitated Fe(OH)₃ with acetylacetone.^[2]

Fe(OH)₃ + 3 HC₅H₇O₂ → Fe(C₅H₇O₂)₃ + 3 H₂O

Structure and properties

Fe(acac)₃ is an octahedral complex with six equivalent Fe-O bonds with bond distances of about 2.00 Å. The regular geometry is consistent with a high-spin Fe³⁺ core with sp3d2 hybridization. As the metal orbitals are all evenly occupied the complex is not subject to Jahn-Teller distortions and thus adopts a D₃ molecular symmetry. In contrast, the related metal acetylacetonate Mn(acac)₃ adopts a more distorted octahedral structure.^[3] The 5 unpaired d-electrons also result in the complex being paramagnetic, with a magnetic moment of 5.90 μ_B.

Fe(acac)₃ possesses helical chirality. The Δ- and Λ-enantiomers slowly inter-convert via Bailar and Ray–Dutt twists. The rate of interconversion is sufficiently slow to allow its enantiomers to be partially resolved.^[4]

Reactions

Fe(acac)₃ has been examined as a precatalyst and reagent in organic chemistry, although the active iron-containing species is usually unidentified in these processes. In one instance, Fe(acac)₃ was shown to promote cross-coupling a diene to an olefin.^[5] Fe(acac)₃ catalyzes the dimerization of isoprene to a mixture of 1,5-dimethyl-1,5-cyclooctadiene and 2,5-dimethyl-1,5-cyclooctadiene.^[6]

Fe(acac)₃ also catalyzes the ring-opening polymerization of 1,3-benzoxazine.^[7] Beyond the area of polymerization, Fe(acac)₃ has been found to catalyze the reaction of N-sulfonyl oxaziridines with olefins to form 1,3-oxazolidine products.^[8]