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Journal articles
Synthetic, Optical and Theoretical Study of Alternating Ethylenedioxythiophene-Pyridine Oligomers: Evolution from Planar Conjugated to Helicoidal Structure towards a Chiral Configuration
Abstract : A series of alternating 3,4-ethylenedioxythiophene-alkynylpyridine oligomers (DA)n with increased solubility are synthesized and their photophysical properties and nonlinear optical properties are investigated. Their quadratic polarizabilities are determined from hyper-Rayleigh scattering experiments to obtain information on their conformations in solution. These chromophores, based on the alternation of electron-rich (D) and electron-deficient (A) moieties, exhibit optical properties that arise from the combination of dipolar and helicoidal features in the (DA)n homologue series where n=1-4. The transition from dipolar conjugated planar structures (n=1, 2) to helicoidal structures (n=3, 4) is clearly evidenced by results from symmetry-sensitive second-order nonlinear optical experiments. This suggests an approach towards highly efficient chiral chromophores for second-order nonlinear optics. Interestingly, this structural evolution also has significant impact on the photophysical properties: both absorption and fluorescence emission show bathochromic and hyperchromic shifts with increasing number of repeating units in the dipolar planar derivatives (n=1-2) but show saturation effects in the helicoidal structures (n=2-4). In addition, the helicoidal structures show sizeable two-photon absorption at 700-750 nm (40-100 GM) for compounds lacking either electron-donating or electron-withdrawing substituents.
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01446723
Contributor : Laurent Jonchère <>
Submitted on : Thursday, January 26, 2017 - 11:37:46 AM
Last modification on : Tuesday, January 12, 2021 - 4:49:41 PM
Contributor : Laurent Jonchère <>
Submitted on : Thursday, January 26, 2017 - 11:37:46 AM
Last modification on : Tuesday, January 12, 2021 - 4:49:41 PM
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