Synthesis, Photophysics and Nonlinear Optical Properties of Stilbenoid Pyrimidine-Based Dyes Bearing Methylenepyran Donor Groups


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Achelle S., Malval J., Aloise S., Barsella A., Spangenberg A., Mager L., ...More

CHEMPHYSCHEM, vol.14, no.12, pp.2725-2736, 2013 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 14 Issue: 12
  • Publication Date: 2013
  • Doi Number: 10.1002/cphc.201300419
  • Title of Journal : CHEMPHYSCHEM
  • Page Numbers: pp.2725-2736
  • Keywords: chromophores, conjugation, heterocycles, nonlinear optics, photophysics, INTRAMOLECULAR CHARGE-TRANSFER, SUBPICOSECOND TRANSIENT ABSORPTION, ENHANCED 2-PHOTON ABSORPTION, TIME-RESOLVED FLUORESCENCE, DUAL EXCITED-STATES, CIS PHOTOISOMERIZATION, NLO PROPERTIES, 4-DIMETHYLAMINO 4-CYANOSTILBENE, SUBSTITUTED TRIPHENYLBENZENE, COOPERATIVE ENHANCEMENT

Abstract

The nonlinear properties and the photophysical behavior of two -conjugated chromophores that incorporate an electron-deficient pyrimidine core (A) and -methylenepyrans as terminal donor (D) groups have been thoroughly investigated. Both dipolar and quadrupolar branching strategies are explored and rationalized on the basis of the Frenkel exciton model. Even though a cooperative effect is clearly observed if the dimensionality is increased, the nonlinear optical (NLO) response of this series is moderate if one considers the nature of the D/A couple and the size of the chromophores (as measured by the number of electrons). This effect was attributed to a disruption in the electronic conjugation within the dyes' scaffold for which the geometry deviates from planarity owing to a noticeable twisting of the pyranylidene end-groups. This latter structural parameter also has a strong influence on the excited-state dynamics, which leads to a very efficient fluorescence quenching.