Publication detail

Spectral characteristics of bisthiophenes and terthiophenes linked with heterocyclic unit in solution and polymer matrix

P. Hrdlovic, J. Krajcovic, D. Vegh

Original Title

Type

journal article - other

Language

English

Original Abstract

Spectral characteristics of derivatives of thiophene substituted on hetoroaromatic cycle as pyrazine was compared with terthiophene linked with cyano and hydrazo groups. The absorption, fluorescence and its lifetime were measured in solution (methanol, cyclohexane) and in polymer matrices (polystyrene, PS; polymethyl methacrylate, PMMA; and polyvinyl chloride, PVC). Derivatives with two thiophene units substitute on pyrazine exhibit the lowest wavenumber band in the region 26,320–25,600 cm(minus 1) and log E = 4.0, which is not influenced by the medium. Derivatives with benzene and pyridine ring annealed to pyrazine (2,3-bis-(2-thienyl)quinoxaline (I), 2,3-bis-(2-thienyl)pyrido[2,3-b]pyrazine (III)) exhibit fluorescence in polar methanol with maximum at 22,200 cm(minus 1) and quantum yield of about 0.2 which is blue-shifted in going to non-polar solvent. The maximum fluorescence is slightly blue-shifted in polymer matrices as compared to methanol. Derivatives with annealed thiophene to pyrazine or substituted with two cyano groups (2,3-bis-(2-thienyl)thieno[3,4-b]pyrazine (II), 2,3-dicyano-5,6-bis(2-thienyl)pyrazine (IV)) do not yield any emission. Derivatives with terthiophene structural units ([2,2,5,2]-terthiophene-[2]-thienylacrylonitrile (V) [2,2,5,2]-terthiophene-5-carbaldehydehydrazone (VI)) exhibit fluorescence with maximum around 20,000 cm (minus 1). The lifetime of fluorescence of all thiophenewas 1 ns or shorter. The polymer matrices increase the intensity of fluorescence to some extent and prolong the lifetime of thiophene derivatives. Derivative VI exhibits some tendency to an aggregation at higher concentration above 0.01 mol kg (minus 1) in polymer matrices.

Keywords

Thiophenes; Terthiophenes; Pyrazines; Polymer matrices; Absorption; Fluorescence; Lifetime

Authors

P. Hrdlovic, J. Krajcovic, D. Vegh

Released

7. 8. 2001

Publisher

ELSEVIER

ISBN

1873-2666

Periodical

Journal of Photochemistry and Photobiology A: Chemistry

Year of study

144

State

unknown

Pages from

Pages to

Pages count

BibTex

@article{BUT104747,
  author="Jozef {Krajčovič}",
  title="Spectral characteristics of bisthiophenes and terthiophenes linked with heterocyclic unit in solution and polymer matrix",
  journal="Journal of Photochemistry and Photobiology A: Chemistry",
  year="2001",
  volume="144",
  pages="73--81",
  issn="1873-2666"
}