Ferrocenecarboxylic acid

Ferrocenecarboxylic acid
Names
	IUPAC name Ferrocenecarboxylic acid
	Other names Ferrocenemonocarboxylic acid
Identifiers
CAS Number	1271-42-7 ;
3D model (JSmol)	Interactive image;
ChemSpider	26585892;
ECHA InfoCard	100.013.673
PubChem CID	15764230;
CompTox Dashboard (EPA)	DTXSID40925783 ;
	InChI InChI=1S/C6H5O2.C5H5.Fe/c7-6(8)5-3-1-2-4-5;1-2-4-5-3-1;/h1-4H,(H,7,8);1-5H;/q2*-1;+2 Key: BAJHDUZEIKRKAS-UHFFFAOYSA-N;
	SMILES [CH-]1C=CC=C1.C1=C[C-](C=C1)C(=O)O.[Fe+2];
Properties
Chemical formula	C11H10FeO2
Molar mass	230.044 g·mol−1
Appearance	yellow solid
Density	1.862 g/cm3
Melting point	214–216 °C (417–421 °F; 487–489 K)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Ferrocenecarboxylic acid is the organoiron compound with the formula (C₅H₅)Fe(C₅H₄CO₂H). It is the simplest carboxylic acid derivative of ferrocene. It can be prepared in two steps from ferrocene by acylation with a 2-chlorobenzoyl chloride followed by hydrolysis.^[2]

Reactions and derivatives

The pK_a of ferrocenecarboxylic acid is 7.8. The acidity increases more than a thousand-fold, to pH 4.54 upon oxidation to the ferrocenium cation.^[3]

By treatment with thionyl chloride, the carboxylic acid anhydride ([(C₅H₅)Fe(C₅H₄CO)]₂O) is produced.^[4]^[5]

Derivatives of ferrocenecarboxylic acid are components of some redox switches.

Related compounds

References

^ Lin, Lily; Berces, Attila; Kraatz, Heinz-Bernhard (1998). "Ferrocenic acid derivatives: Towards Rationalizing Changes in the Electronic and Geometric Structures". Journal of Organometallic Chemistry. 556 (1–2): 11–20. doi:10.1016/S0022-328X(97)00785-7.
^ Perry C. Reeves (1977). "Carboxylation of Aromatic Compounds: Ferrocenecarboxylic Acid". Organic Syntheses. 56: 28. doi:10.15227/orgsyn.056.0028.
^ Fabbrizzi, Luigi (2020). "The Ferrocenium/Ferrocene Couple: A Versatile Redox Switch". Chemtexts. 6 (4). doi:10.1007/s40828-020-00119-6. S2CID 222215803.
^ Tazi, Mehdi; Roisnel, Thierry; Mongin, Florence; Erb, William (2017). "Ferrocenecarboxylic Anhydride: Identification of a New Polymorph" (PDF). Acta Crystallographica Section C Structural Chemistry. 73 (10): 760–766. doi:10.1107/S205322961701124X. PMID 28978780. S2CID 4437353.
^ Lau, Hans; Hart, Harold (1959). "Notes- Preparation and Hydrolysis of Crystalline Ferrocenoyl Chloride". The Journal of Organic Chemistry. 24 (2): 280–281. doi:10.1021/jo01084a647.

[1] Lin, Lily; Berces, Attila; Kraatz, Heinz-Bernhard (1998). "Ferrocenic acid derivatives: Towards Rationalizing Changes in the Electronic and Geometric Structures". Journal of Organometallic Chemistry. 556 (1–2): 11–20. doi:10.1016/S0022-328X(97)00785-7.

[2] Perry C. Reeves (1977). "Carboxylation of Aromatic Compounds: Ferrocenecarboxylic Acid". Organic Syntheses. 56: 28. doi:10.15227/orgsyn.056.0028.

[3] Fabbrizzi, Luigi (2020). "The Ferrocenium/Ferrocene Couple: A Versatile Redox Switch". Chemtexts. 6 (4). doi:10.1007/s40828-020-00119-6. S2CID 222215803.

[4] Tazi, Mehdi; Roisnel, Thierry; Mongin, Florence; Erb, William (2017). "Ferrocenecarboxylic Anhydride: Identification of a New Polymorph" (PDF). Acta Crystallographica Section C Structural Chemistry. 73 (10): 760–766. doi:10.1107/S205322961701124X. PMID 28978780. S2CID 4437353.

[5] Lau, Hans; Hart, Harold (1959). "Notes- Preparation and Hydrolysis of Crystalline Ferrocenoyl Chloride". The Journal of Organic Chemistry. 24 (2): 280–281. doi:10.1021/jo01084a647.

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