Title

Electrochemistry of fullerenes and fullerene derivatives

Date of Award

1997

Availability

Article

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Chemistry

First Committee Member

Luis Echegoyen, Committee Chair

Abstract

Chapter 1. The anodic electrochemistry of corannulene, cyclopentacorannulene, and compounds 10, 32, and 14 has been studied under different conditions. With the exception of cyclopentacorannulene, all the compounds decompose during the first or second electrochemical reductions. The mono- and dianionic states of corannulene, cyclopentacorannulene, and 10 were chatacterized by UV-Vis and ESR spectroscopies.Chapter 2. The oxidative eletrochemistry of C$\sb{60}$, C$\sb{70}$, and the higher fullerenes has been studied. Chemically and eletrochemically reversible one-electron oxidation processes were found for all the fullerene compounds. Second one-eletron oxidation processes were detected for C$\sb{70}$, C$\sb{76}$, and C$\sb{78}$. Different reduction waves were observed for the two isomers of C$\sb{78}$. The energy separation between the first oxidation and reduction waves are in good agreement with the predicted HOMO-LUMO energy differences.Chapter 3. Electrochemical studies on six C$\sb{60}$ derivatives have been performed at very negative potentials. The electrochemistry of the Diels-Alder adducts is characterized by four reversible reduction waves followed by the decomposition of the tetraanionic species into stable carbanions. The isomers of the diazomethane adducts present separate fifth reduction processes which are $\sim$0.20 V apart. Thermalization of the fulleroid isomers into their methanofullerene structures was followed by CV, OSWV, and UV-Vis spectroscopy. A new chemical step was observed after the fifth reduction wave of the methanofullerene isomers. The generated electroactive produce a new set of anodic waves, which may correspond to a carbanion structure obtained by breakage of the cyclopropane ring of the highly charged methanofullerenes.Chapter 4. The formation of a secondary fullerene monolayer was achieved by hydrogen bonding between the ammonium groups of cystamine derivatized gold beads and the crown ether moiety of 47. The fullerene monolayer was detected by OSWV and corroborated by control experiments with C$\sb{60}$ and 48. The fullerene surface coverage is in good agreement with calculations assuming fcc packing and an area of 100 A$\sp2$ per C$\sb{60}$ molecule.

Keywords

Chemistry, Analytical; Chemistry, Physical

Link to Full Text

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