Synthesis of tris(acetylacetonato)iron(III) [Fe(C₅H₇O₂)₃] by reaction between Fe(OH)₃ and acetylacetone (acac) by green chemistry method.

 Synthesis of Tris(acetylacetonato)iron(III)

[Fe(C₅H₇O₂)₃]

Aim

To synthesize tris(acetylacetonato)iron(III) $[Fe(C₅H₇O₂)₃]$ by the reaction between Fe(OH)₃ and acetylacetone (acac) using a green chemistry method.

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Principle

Acetylacetone (2,4-pentanedione) acts as a bidentate ligand and coordinates with Fe³⁺ ions to form a stable octahedral complex.

In alkaline medium, acetylacetone loses a proton to form the acetylacetonate ion (acac⁻) which coordinates with Fe³⁺ through two oxygen atoms. Three acetylacetonate ligands combine with Fe³⁺ to form the complex tris(acetylacetonato)iron(III).

The complex is formed using a green chemistry approach, which avoids harmful solvents and minimizes waste.

Reaction

$$$$Fe(OH)3+3Hacac→Fe(acac)3+3H2O

Where
acac = Acetylacetone

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Requirements

Chemicals

Ferric hydroxide Fe(OH)₃, Acetylacetone (acac), Sodium acetate (buffer), Ethanol or distilled water

Apparatus 

Beaker, Glass rod, Water bath, Funnel, Filter paper, Measuring cylinder

Procedure

1. Take about 1 g of ferric hydroxide (Fe(OH)₃) in a beaker.

2. Add 10–15 mL acetylacetone to the beaker.

3. Add a small amount of sodium acetate to maintain suitable pH.

4. Stir the mixture and heat it gently on a water bath for about 10–15 minutes.

5. The reaction mixture gradually forms a reddish-brown solution indicating formation of the complex.

6. Allow the solution to cool slowly.

7. Red crystalline solid of tris(acetylacetonato)iron(III) separates out.

8. Filter the crystals using filter paper.

9. Wash the crystals with cold ethanol and dry between filter papers.

Observation

Observation	Result
Colour of Fe(OH)₃	Brown
Colour of reaction mixture	Reddish brown
Colour of crystals obtained	Red

Result

Tris(acetylacetonato)iron(III) complex $[Fe(C₅H₇O₂)₃]$ was successfully synthesized as red crystals.