Photophysics and self-assembly of symmetrical and unsymmetrical cationic oligophenylene ethynylenes

A study of the synthesis, photophysical behavior and self-assembly of a series of symmetrical cationic oligophenylene ethynylenes is reported. Aqueous solutions of all these compounds exhibit strong and structured absorption in the ultraviolet (maxima near 305 nm and 355 nm) with a broad fluorescence in the range 370-600 nm. While all of these compounds show strong fluorescence in methanol, the fluorescence yields in water are variable and substituent dependent. Transient absorption, presumably attributable to a triplet is found for all of the oligomers studied thus far. All of the compounds having a net positive charge exhibit strong complex formation when they are added to aqueous solutions containing the anionic biopolymer carboxymethylcellulose. The complexes are characterized by a pronounced red shift in the oligomer absorption spectrum and a red shifted and generally intense fluorescence. We attribute the spectral shifts due to the formation of "J-dimers" in each case. The results of this preliminary study suggest that these compounds may be useful in sensing due to their strong tendency to associate with anionic biomacromolecules. © 2009 Elsevier B.V. All rights reserved.

Full Text

Duke Authors

Cited Authors

  • Tang, Y; Zhou, Z; Ogawa, K; Lopez, GP; Schanze, KS; Whitten, DG

Published Date

  • 2009

Published In

Volume / Issue

  • 207 / 1

Start / End Page

  • 4 - 6

International Standard Serial Number (ISSN)

  • 1010-6030

Digital Object Identifier (DOI)

  • 10.1016/j.jphotochem.2009.03.006