Donor/acceptor interactions in self-assembled monolayers and their consequences on interfacial electron transfer

Eden J. Pacsial, Daniel Alexander, Robert J. Alvarado, Massimiliano Tomasulo, Francisco Raymo

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The supramolecular association of tetrathiafulvalene (TTF) donors and bipyridinium acceptors is employed routinely to direct the formation of host/guest complexes and interlocked molecules in bulk solution. We have reproduced these donor/acceptor interactions at electrode/solution interfaces and demonstrated their pronounced influence on heterogeneous electron transfer. Specifically, we have synthesized a TTF with an oligomethylene arm terminated by a thiol group and assembled monolayers of this compound on gold. We have observed that the cyclic voltammogram of the immobilized TTF donors varies significantly upon addition of benzyl viologen, tetracyanoquinodimethane (TCNQ), or tetracyanoethylene (TCNE) acceptors to the electrolyte solution. Indeed, the supramolecular association of the complementary donors and acceptors results in a pronounced current decrease for the TTF redox waves. Consistently, the electrochemical response of the acceptors changes dramatically in the presence of TTF donors on the electrode surface. Instead, hexadecanethiolate monolayers, lacking the TTF donors at the termini of the oligomethylene chains, have a marginal influence on the voltammograms of the acceptors. Impedance measurements indicate that the charge-transfer resistance (R CT) for the reduction of the acceptors increases from less than 0.3 kΩ, at bare gold, to 324, 24, and 43 kΩ for benzyl viologen, TCNQ, and TCNE, respectively, at TTF-coated electrodes. By contrast, the electrode coating has a negligible influence on the cyclic voltammogram and impedance response of ferrocene, which cannot sustain donor/acceptor interactions with the immobilized TTFs. Thus, our results demonstrate that the interfacial complexation of complementary donors and acceptors has a dramatic effect on the heterogeneous electron transfer to and from the associated components.

Original languageEnglish
Pages (from-to)19307-19313
Number of pages7
JournalJournal of Physical Chemistry B
Volume108
Issue number50
DOIs
StatePublished - Dec 16 2004

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Self assembled monolayers
electron transfer
Electrodes
electrodes
Electrons
Benzyl Viologen
Monolayers
Gold
Association reactions
interactions
gold
impedance measurement
Complexation
thiols
Charge transfer
Electrolytes
charge transfer
electrolytes
impedance
coatings

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

Donor/acceptor interactions in self-assembled monolayers and their consequences on interfacial electron transfer. / Pacsial, Eden J.; Alexander, Daniel; Alvarado, Robert J.; Tomasulo, Massimiliano; Raymo, Francisco.

In: Journal of Physical Chemistry B, Vol. 108, No. 50, 16.12.2004, p. 19307-19313.

Research output: Contribution to journalArticle

Pacsial, Eden J. ; Alexander, Daniel ; Alvarado, Robert J. ; Tomasulo, Massimiliano ; Raymo, Francisco. / Donor/acceptor interactions in self-assembled monolayers and their consequences on interfacial electron transfer. In: Journal of Physical Chemistry B. 2004 ; Vol. 108, No. 50. pp. 19307-19313.
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