Bis(acetylacetonato)iron(II)

Bis(acetylacetonato)iron(II)

Names
IUPAC name Bis(2,4-pentanedionato-κO,κO')iron
Other names Bis(2,4-pentanedionato)iron Ferrous acetylacetonate Iron(II) 2,4-pentanedionate
Identifiers
CAS Number	14024-17-0  Y
3D model (JSmol)	Interactive image hydrate: Interactive image
ChemSpider	4589054
ECHA InfoCard	100.034.397
EC Number	237-851-4
PubChem CID	5486775 hydrate: 134687727
InChI InChI=1S/2C5H8O2.Fe/c2*1-4(6)3-5(2)7;/h2*3,6H,1-2H3;/q;;+2/p-2/b2*4-3-; Key: LFORAFQNBQKDRY-FDGPNNRMSA-L hydrate:InChI=1S/2C5H8O2.Fe.H2O/c2*1-4(6)3-5(2)7;;/h2*3,6H,1-2H3;;1H2/b4-3-;;; Key: XTPSXHDLJKIQTA-FGSKAQBVSA-N
SMILES C/C(=C/C(=O)C)/[O-].C/C(=C/C(=O)C)/[O-].[Fe+2] hydrate:CC(=CC(=O)C)O.C/C(=C/C(=O)C)/O.O.[Fe]
Properties
Chemical formula	C10H14FeO4
Molar mass	254.063 g·mol−1
Melting point	170–171 °C (338–340 °F; 443–444 K)
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P264, P264+P265, P271, P280, P302+P352, P304+P340, P305+P351+P338, P319, P321, P332+P317, P337+P317, P362+P364, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Bis(acetylacetonato)iron(II) is a coordination complex with the formula [Fe(C₅H₇O₂)₂]₂. It is a dark, nearly black, air-sensitive, sublimable solid. It can be prepared by treating ferrous salts with 2,4-pentanedione in presence of base. ^[1]

Structure

Structure of Fe₂(acetylacetonate)₄ Color code: red = O, blue = Fe. The pentacoordinate Fe is on the left.

The structure of the complex has been confirmed by X-ray crystallography. As found for some other bis(acetylacetonates) (e.g., the nickel(II) and cobalt(II) derivatives), bis(acetylacetonato)iron(II) is not a monomer. It contains two Fe centers, one octahedral and one pentacoordinate. Three of the acetylacetonato ligands bridge the two Fe centers.

Reactions

The dimeric structure of bis(acetylacetonato)iron(II) is readily cleaved by Lewis bases to give adducts Fe(C₅H₇O₂)₂L₂. Examples include the dihydrate ^[3] and the tmeda complex. ^[4]

Bis(acetylacetonato)iron(II) is used as an anhydrous, "organic soluble" source of Fe(II). For example, it reacts with lithium bis(hydropentalenyl)iron to afford green [(C₈H₇)Fe]₂-[(C₈H₈)₂Fe], a quadruple-decker complex. ^[5] It also reacts with Li₂Pn^*(TMEDA)_x (Pn^* = permethylpentalene) to yield purple-black Fe₂Pn^*₂. ^[6]

References

1. Manríquez, J. M., Bunel, E. E., Oelckers, B., Román, E., Vv́squez, C., & Miller, J. S. (2007). Bis(2,4-Pentanedionato)Iron(II) [Iron(II) Bis(Acetylacetonate)]. Inorganic Syntheses, 267–269. doi : 10.1002/9780470132623.ch44
2. Shibata, S.; Onuma, S.; Iwase, A.; Inoue, H. (1977). "The Crystal structure of Dimeric bis(acetylacetonato)iron(II)". Inorganica Chimica Acta. 25: 33–39. doi:10.1016/S0020-1693(00)95687-1.
3. Laugier, J.; Mathieu, J. P. (1975). "Sur la structure du bisacétylacétonate de Fe^II dihydraté". Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry. 31 (2): 631. Bibcode:1975AcCrB..31..631L. doi:10.1107/S0567740875003470.
4. Halz, Jan Henrik; Heiser, Christian; Wagner, Christoph; Merzweiler, Kurt (2020). "Syntheses and crystal structures of three [M(Acac)₂(TMEDA)] complexes ( M = Mn, Fe and Zn)". Acta Crystallographica Section E: Crystallographic Communications. 76 (1): 66–71. Bibcode:2020AcCrE..76...66H. doi:10.1107/S2056989019016372.
5. Oelckers, B., Chavez, I., Manriquez, J. M., & Roman, E. (1993). On the way to delocalized organometallic polymers: triple- and quadruple-decker pentalene complexes of iron and cobalt. Organometallics, 12(9), 3396–3397. doi : 10.1021/om00033a007
6. Binding, S. C., Green, J. C., Myers, W. K., & O’Hare, D. (2015). Synthesis, Structure, and Bonding for Bis(permethylpentalene)diiron. Inorganic Chemistry, 54(24), 11935–11940. doi : 10.1021/acs.inorgchem.5b02254