Oligomers of “Extended Viologen”,
<i>p</i>-Phenylene-bis-4,4‘-(1-aryl-2,6-diphenylpyridinium), as
Candidates for Electron-Dopable Molecular Wires
Michal Valášek
Jaroslav Pecka
Jindřich
Gérard Calleja
Peter R. Craig
Josef Michl
10.1021/jo049142s.s001
https://acs.figshare.com/articles/journal_contribution/Oligomers_of_Extended_Viologen_i_p_i_-Phenylene-bis-4_4_-_1-aryl-2_6-diphenylpyridinium_as_Candidates_for_Electron-Dopable_Molecular_Wires/4009056
We report the synthesis and spectral characterization of the first five members of an oligomeric
series built from alternating <i>p</i>-connected 1,4-benzene and 1,4-pyridinium rings, <b>1[</b><b><i>n</i></b><b>]</b>−<b>4[</b><b><i>n</i></b><b>]</b>, <i>n</i> =
1−5, with <i>p</i>-phenylene-bis-4,4‘-(1-aryl-2,6-diphenylpyridinium) (“extended viologen”) as the repeating unit. The lengths of these rodlike molecules range from 2 to 9 nm. The monomer was obtained
from <i>p-</i>phenylene-bis-4,4‘-(2,6-diphenylpyrylium) (<b>5</b>) and <i>p-</i>phenylenediamine (<b>6</b>) or <i>p</i>-aminoacetanilide (<b>9</b>). Higher oligomers were synthesized by stepwise elaboration of the monomer by reactions
with the appropriate bis-pyrylium (<b>5</b>) or pyrylium-phenylene-pyridinium (<b>8</b>) salts. Eight different
counterions were used, and dodecamethylcarba-<i>closo</i>-dodecaborate was found to offer particularly
favorable solubility characteristics. Ultraviolet absorption spectra of the oligomers suggest that
the individual extended viologen segments interact only weakly, as a result of the strongly twisted
orientation of the benzene rings that separate them. The UV spectrum of the monomer was
interpreted by comparison with semiempirical INDO/S calculations performed at a DFT optimized
geometry.
2005-01-21 00:00:00
Electron-Dopable Molecular Wires
DFT optimized geometry
Ultraviolet absorption spectra
monomer
9 nm
UV spectrum
phenylene-bi
benzene rings
rodlike molecules range
viologen segments
oligomeric series
solubility characteristics
INDO