Title | Oligomers of “Extended Viologen”, p-Phenylene-bis-4,4‘-(1-aryl-2,6-diphenylpyridinium), as Candidates for Electron-Dopable Molecular Wires |
Publication Type | Journal Article |
Year of Publication | 2005 |
Authors | Valasek M, Pecka J, Jindrich, Calleja G, Craig PR, Michl J |
Journal | The Journal of Organic Chemistry |
Volume | 70 |
Issue | 2 |
Pagination | 405 - 412 |
Date Published | 2005/01/01/ |
Abstract | We report the synthesis and spectral characterization of the first five members of an oligomeric series built from alternating p-connected 1,4-benzene and 1,4-pyridinium rings, 1[n]4[n], n = 15, with p-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 p-phenylene-bis-4,4`-(2,6-diphenylpyrylium) (5) and p-phenylenediamine (6) or p-aminoacetanilide (9). Higher oligomers were synthesized by stepwise elaboration of the monomer by reactions with the appropriate bis-pyrylium (5) or pyrylium-phenylene-pyridinium (8) salts. Eight different counterions were used, and dodecamethylcarba-closo-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. |
URL | http://dx.doi.org/10.1021/jo049142s |
Short Title | J. Org. Chem. |