Synthesis, Crystal Structure, and Electrochemistry of Mono- and Bis-Homoannular Ferrocene Derivatives

Synthesis, Crystal Structure, and Electrochemistry of Mono- and Bis-Homoannular Ferrocene Derivatives

Two ferrocene derivatives, namely, 1,2-(tetramethylene)-ferrocene and 1,2,1′,2′-bis(tetramethylene)-ferrocene, were synthesized in a four-step reaction sequence starting from ferrocene. Friedel–Crafts acylation of ferrocene using succinic anhydride gave mono- or bis(3-carboxypropinoyl)-ferrocene dep...

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Bibliographic Details
Published in:Crystals (Basel) Vol. 14; no. 2; p. 141
Main Authors: Pokharel, Uttam R., Daigle, Derek P., Naquin, Stone D., Engeron, Gwyneth S., Lo, Mary A., Fronczek, Frank R.
Format: Journal Article
Language:English
Published: Basel MDPI AG 01-01-2024
Subjects:
1,2-(tetramethylene)-ferrocene
1,2-(α-ketotetramethylene)-ferrocene
Acylation
Aluminum
Anhydrides
Carbon
Chloride
Clemmensen reduction
Column chromatography
Crystal structure
Crystals
Diketones
Electrochemical reactions
Electrochemistry
ferrocene
Friedel–Crafts acylation
Hydrocarbons
Iron compounds
Metallocenes
Methylene
Molecular structure
Oxidation
Reduction
Single crystals
Stereochemistry
Stoichiometry
Structure
X ray analysis
X-ray crystallography
United States > US
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Summary:Two ferrocene derivatives, namely, 1,2-(tetramethylene)-ferrocene and 1,2,1′,2′-bis(tetramethylene)-ferrocene, were synthesized in a four-step reaction sequence starting from ferrocene. Friedel–Crafts acylation of ferrocene using succinic anhydride gave mono- or bis(3-carboxypropinoyl)-ferrocene depending on the stoichiometry of succinic anhydride. The reduction of the keto groups to methylene followed by ring-closing using trifluoroacetic anhydride gave 1,2-(α-ketotetramethylene)-ferrocene or 1,2,1′,2′-bis(α-ketotetramethylene)-ferrocene. The diastereomeric mixture of the latter diketones was separated using column chromatography, characterized via single-crystal X-ray analysis, and assigned its stereochemistry. Reduction of the keto groups to methylene under Clemmensen conditions gave homoannular mono- or bis(tetramethylene)-ferrocene derivatives. The molecular structure of 1,2-(tetramethylene)-ferrocene revealed that the ipso carbon atoms of the cyclopentadienyl group are 0.023(3) Å farther away from Fe(II) compared to the remaining three carbon atoms. Both complexes exhibit lower half-wave oxidation potentials than ferrocene, possibly due to the electron-releasing effects of the tetramethylene bridges.
ISSN:2073-4352
2073-4352
DOI:10.3390/cryst14020141