New Multifunctional Bipyrimidine-Based Chromophores for NLO-Active Thin-Film Preparation**

Bora U., Abdallah S., Mhanna R., Nicolas P., Dok A., de Coene Y., ...More

Chemistry - A European Journal, vol.30, no.4, 2024 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 30 Issue: 4
  • Publication Date: 2024
  • Doi Number: 10.1002/chem.202302930
  • Journal Name: Chemistry - A European Journal
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Agricultural & Environmental Science Database, Applied Science & Technology Source, Biotechnology Research Abstracts, Chemical Abstracts Core, Chimica, Compendex, EMBASE, MEDLINE
  • Keywords: bipyrimidine, chirality, liquid crystals, nonlinear optics, thin films
  • Yıldız Technical University Affiliated: Yes


New synthesized bipyrimidine-based chromophores presenting alkoxystyryl donor groups carrying aliphatic achiral and chiral chains in the 4 position, connected to electron-accepting 2,2-bipyrimidine cores have been synthesized. Their linear and nonlinear optical (NLO) properties were investigated as well as their mesomorphic properties by various techniques (light-transmission measurements, polarized-light optical microscopy, differential scanning calorimetry measurements and two-photon excited fluorescence). The derivatives with achiral linear carbon chains were found to exhibit liquid-crystal properties with the formation smectic phases over large temperature ranges, which were confirmed by small-angle X-ray scattering analysis via stacking models. The nonlinear optical properties in the solid state for derivatives with C14 and the citronellol chains have been studied by wide-field second-harmonic generation and multi-photon fluorescence imaging, confirming centrosymmetry for these achiral mesogens and their excellent third-order nonlinearity whereas the chiral compound exhibits non-centrosymmetric organization resulting in a strong Second Harmonic Generation at the crystal state.