Experimental Design

Removal of Chloride Atoms

The acylating reagent was formed using the Friedel-Crafts method, by mixing the acyl-chloride, either suberoyl-chloride, dodecanedioyl-dichloride, or glutaryl-dichloride, with an excess of aluminum chloride in dichloromethane at zero degrees Celsius under a nitrogen atmosphere (Figure 1). The aluminum chloride was used to remove the two chlorine atoms and form the acylating reagent.

Attachment of the Acylating Reagent to the Ferrocene Caps

The acylating reagent was then transferred to a round-bottomed flask, containing ferrocene in dichloromethane, via a cannula at zero degrees Celsius. The reaction was allowed to stir for two hours. The acylating reagent was transferred to the ferrocene molecules via a cannula in order to avoid any interaction with the atmosphere. Upon completion of the cannulation, the solution was poured into an ice-water mixture containing sodium thiosulfate, in order to reduce the ferrocene cations, which formed during the reaction. This reaction between the sodium thiosulfate and the ferrocene cations was allowed to stir for roughly fifteen minutes.

"Washing" and "Drying" of the Molecule

Upon completion of the reaction, the aqueous layer was separated off via a separatory funnel and disposed of. The organic layer, containing the ferrocene derivatives, was washed with sodium bicarbonate. The "washing" process was performed in hopes of mitigating the amount of undesired products. The starting materials and the unwanted byproducts of these reactions are polar and, therefore, soluble in water and sodium bicarbonate. Once the organic layer was "washed," the inorganic layer was separated off and disposed of. The aqueous layer, containing the ferrocene derivatives, was placed in an Erlenmeyer flask and left for fifteen hours to dry over magnesium sulfate. This was done to assure that no water was present in the sample. The magnesium sulfate was used to absorb the water, therefore leaving only the desired products in the organic layer. After the process of drying the organic layer the solution was run through a frit in order to completely rid the solution of any magnesium sulfate that may have been transferred with the desired solution. The product was then removed under reduced pressure via a rotoevaporation apparatus.

Analyses

The product was then analyzed using hydrogen and carbon-13 NMR spectroscopy, mass spectrometry, and infrared spectroscopy. These analyses were performed to assure that the acylating reagent had attached to the ferrocene molecules, along with making sure that the chlorine atoms had been removed from the alkane.

Reduction of the Molecule

The reduction of the molecule, reducing the ketone (where the carbon double bond to an oxygen atom goes to a carbon atom containing two single hydrogen bonds), was achieved by adding lithium aluminum hydride to a solution of aluminum chloride and the ferrocene compound in dry ether (Figure 1). The aluminum chloride was used to pull the oxygen atoms away from the carbon atom, therefore allowing the hydrogen atoms, from the lithium aluminum hydride, to attach themselves to the carbon atoms. Upon the solution turning yellow, indicating that the molecule had become reduced, an excess of water was added to the solution and the organic layer was separated off and disposed of. The ether layer was washed again with water and then allowed to dry over magnesium sulfate for roughly fifteen hours. The reduced ferrocene compound was then removed under reduced pressure. The product was tested for purity via thin layer chromatography (TLC). If the TLC plates showed any sign of contamination, the product was repurified through a silica gel column.

Electrochemistry

After final purification and spectral analysis the product's electrochemical properties were tested using a potentiostat employing a three electrode electrochemical cell. This apparatus was used to find the oxidation potentials of the ferrocene caps, with respect to the insulating acyl chain length. Three mL of a 0.1 molar electrolyte solution was used to test the redox potentials. The amount of the compound used varied, depending on its molecular weight; however, in all cases a 0.001 molal solution was used to test the redox potentials. Once the apparatus was set up the three compounds were individually placed in the electrochemical solution, and the redox potentials were graphed against each other on a computer.

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Abstract | Introduction | Experimental Design | Results & Discussion | Conclusion