Chromium(III) acetylacetonate

Chromium(III) acetylacetonate^[1]

Solid chromium(III) acetylacetonate
Names
IUPAC name Chromium(III) acetylacetonate
Other names Tris(2,4-pentanediono)chromium(III)
Identifiers
CAS Number	21679-31-2 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:33035 Y
ChemSpider	2006256 Y
ECHA InfoCard	100.040.463
InChI InChI=1S/3C5H7O2.Cr/c3*1-4(6)3-5(2)7;/h3*3H,1-2H3;/q3*-1;+3 Y Key: GMJCSPGGZSWVKI-UHFFFAOYSA-N Y InChI=1/3C5H7O2.Cr/c3*1-4(6)3-5(2)7;/h3*3H,1-2H3;/q3*-1;+3 Key: GMJCSPGGZSWVKI-UHFFFAOYAF
SMILES [Cr+3].O=C([CH-]C(=O)C)C.O=C([CH-]C(=O)C)C.O=C([CH-]C(=O)C)C
Properties
Chemical formula	C15H21CrO6
Molar mass	349.32
Appearance	deep maroon
Density	1.34 g/cm3
Melting point	210 °C (410 °F; 483 K)
Boiling point	340 °C (644 °F; 613 K) (sublimes near 100 °C)
Solubility in non-polar organic solvents	soluble
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

Chromium(III) acetylacetonate is the coordination compound with the formula Cr(C₅H₇O₂)₃, sometimes designated as Cr(acac)₃. This purplish coordination complex is used in NMR spectroscopy as a relaxation agent because of its solubility in nonpolar organic solvents and its paramagnetism.

Synthesis and structure

The compound is prepared by the reaction of chromium(III) oxide with acetylacetone (Hacac):^[2]

Cr₂O₃ + 6 Hacac → 2 Cr(acac)₃ + 3 H₂O

The complex has idealized D₃ symmetry. The Cr-O distances are 1.93 Å.^[3] Like other Cr(III) compounds, it has the d³ configuration, having a quartet ground state. Although it is relatively inert toward substitution, the complex undergoes bromination at the 3-positions of the chelate rings.

References

1. ↑ Chromium acetylacetonate at American Elements
2. ↑ W. Conard Fernelius, Julian E. Blanch “Chromium(III) Acetylacetonate: [Tris(2,4-Pentanediono)Chromium(III)]” Inorganic Syntheses, 1957, Volume 5, 130-131.doi:10.1002/9780470132364.ch35
3. ↑ B. Morosin "The crystal structure of trisacetylacetonatochromium(III)" Acta Crystallogr. 1965. vol. 19, 131-137. doi:10.1107/S0365110X65002876