Chromium(III) acetylacetonate
Appearance
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![]() Solid chromium(III) acetylacetonate
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Names | |
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IUPAC name
Chromium(III) acetylacetonate
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Other names
Tris(2,4-pentanediono)chromium(III)
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Identifiers | |
3D model (JSmol)
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ChEBI | |
ChemSpider | |
ECHA InfoCard | 100.040.463 |
CompTox Dashboard (EPA)
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Properties | |
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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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
- ^ Chromium acetylacetonate at American Elements
- ^ 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
- ^ B. Morosin "The crystal structure of trisacetylacetonatochromium(III)" Acta Crystallogr. 1965. vol. 19, 131-137. doi:10.1107/S0365110X65002876