Abstract

RIVERA, Ernesto. Study of the Influence of the Polyacetylene Main Chain Configuration and the Internal Stacking of Pendant Groups over the Optical and Photophysical Properties of trans and cis-Poly(1-pyrenylacetylene)s by UV-Vis and Fluorescence Spectroscopy. Rev. Soc. Quím. Méx [online]. 2004, vol.48, n.1, pp.38-45. ISSN 0583-7693.

The influence of the polyacetylene backbone configuration and the internal stacking of pendant groups over the optical and photophysical properties of trans-poly(1-ethynylpyrene) (trans-PEP) and cis-poly(1-ethynylpyrene) (cis-PEP) was studied by UV-vis and fluorescence spectroscopy. From the absorption spectra of both polymers, it was found that trans-PEP possesses a higher degree of conjugation than its cis analogue. Besides, intramolecular interactions occur between the pendant pyrene units (associated pyrenes) present in each polymer, giving rise to a new emission. These interactions are stronger in cis-PEP due to a coiling of the main polyacetylene chain. Excitation spectra jointly with fluorescence decay profiles show that these interactions occur in the ground state (static excimer).

Keywords : Intramolecular interactions; polyarylacetylenes; pyrene; UV-vis; fluorescence.