ORGANIC
LETTERS
2
007
Vol. 9, No. 15
779-2782
Carbodithioate-Terminated
2
Oligo(phenyleneethynylene)s: Synthesis
and Surface Functionalization of Gold
Nanoparticles
Tae-Hong Park and Michael J. Therien*
Department of Chemistry, UniVersity of PennsylVania, 231 South 34th Street,
Philadelphia, PennsylVania 19104-6323
Received April 2, 2007
ABSTRACT
Carbodithioate-terminated bis(phenylene)ethynylenes and oligo(phenyleneethynylene)s have been synthesized from TMSE-protected 4-io-
dodithiobenzoic acid ester (1) and 4-ethynyldithiobenzoic acid ester (3) via Pd-catalyzed cross-coupling reactions. TEM and spectroscopic
studies demonstrate that the reaction of 4-(phenylethynyl)dithiobenzoate with alkylamine-protected gold nanoparticles (AuNPs) produces the
corresponding organocarbodithioate-functionalized AuNPs.
Oligo(phenyleneethynylene)s (OPEs) have functioned as a
structural mainstay in the field of molecular electronics.
These OPE-based molecular units have featured commonly
a terminal thiol functional group, which provides the point
1
-8
1-8
of attachment to macroscopic metal surfaces or nanoscopic
(1) Cygan, M. T.; Dunbar, T. D.; Arnold, J. J.; Bumm, L. A.; Shedlock,
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Aliphatic dithiocarboxylic acid derivatives have been
shown recently to form well-packed and highly ordered self-
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Frisbie, C. D. AdV. Mater. 2003, 15, 1881-1890.
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11
assembled monolayers (SAMs) on Au surfaces. Dithioben-
zoic acid-modified CdSe quantum dots (QDs) have been
obtained similarly via a ligand exchange protocol; these QD
(
(
(
functionalization reactions are milder than those established
2
12,13
previously for analogous thiol ligands.
The characteristic
(
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D. L.; Tour, J. M.; Weiss, P. S. Science 2001, 292, 2303-2307.
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2
(
1
0.1021/ol070789j CCC: $37.00
© 2007 American Chemical Society
Published on Web 06/29/2007