Closely stacked oligo(phenylene ethynylene)s: Effect of π-stacking on the electronic properties of conjugated chromophores

Subodh P. Jagtap, Sukrit Mukhopadhyay, Veaceslav Coropceanu, Glen L. Brizius, Jean Luc Brédas, David M. Collard*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

81 Scopus citations

Abstract

In this work, a bicyclo[4.4.1]undecane scaffold is used to hold oligo(phenylene ethynylene) units in a cofacially stacked arrangement along the entire length of the conjugated units. We study the impact that the resulting strong interchain interactions have on the photophysical properties. The length of the individual oligomer branches was varied from three to five rings to investigate the effect of conjugation on the electronic properties of the stacked segments. Absorption and fluorescence spectra were recorded and compared to those of the corresponding unstacked analogues. Time-dependent density functional theory calculations were carried out and helped to rationalize the low-energy features present in the fluorescence spectra of the stacked systems. The calculations indicate that the low-energy emissions are due to the presence of excimer-like states. The stronger intensity of the low-energy fluorescence band observed in the five-ring stacked system compared to the three-ring analogue is attributed to the smaller activation barrier that separates the local intrachain state and the excimer-like state in the former compound.

Original languageEnglish (US)
Pages (from-to)7176-7185
Number of pages10
JournalJournal of the American Chemical Society
Volume134
Issue number16
DOIs
StatePublished - Apr 25 2012
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Catalysis
  • Biochemistry
  • Colloid and Surface Chemistry

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