Impact of π-bridge structure on ICT-driven AIE and emission color in TAPP-CSB chromophores


Demirtas F., Gocen E. S., Kahyaoglu Z., YAĞIZ ERDEMİR G.

Journal of Photochemistry and Photobiology A: Chemistry, cilt.481, 2026 (SCI-Expanded, Scopus)

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 481
  • Basım Tarihi: 2026
  • Doi Numarası: 10.1016/j.jphotochem.2026.117454
  • Dergi Adı: Journal of Photochemistry and Photobiology A: Chemistry
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, BIOSIS, Chemical Abstracts Core, Chimica, Compendex, Academic Search Ultimate (EBSCO)
  • Anahtar Kelimeler: AIE mechanism, Bathochromic shift, CIE 1931 chromaticity, ICT system, TAPP-based D-π-a system
  • Gazi Üniversitesi Adresli: Evet

Özet

In this study, two donor-π-acceptor (D-π-A) type TAPP-CSB chromophores containing phenyl and thiophene π-bridges were designed and synthesized; the effect of bridge engineering on excited-state dynamics, aggregation-induced emission (AIE), and emission color modulation was investigated. Systematic photophysical investigations revealed that the thiophene-bridged derivative exhibited significantly stronger intramolecular charge-transfer (ICT) characteristics compared to the phenylene analog, resulting in pronounced bathochromic shifts and large Stokes shifts (up to 6751 cm−1). Studies on solvent-dependent effects have shown that increasing polarity stabilizes the ICT state. It was determined that both chromophores exhibit typical AIE behavior in DMSO/water mixtures, attributed to restricted intramolecular motion (RIM). The CIE 1931 chromaticity analysis quantitatively confirmed the color shift associated with the solvent and aggregation and revealed a broader color distribution for the thiophene-bridged chromophore. Dynamic light scattering (DLS) measurements confirmed the formation of large aggregates in water-rich environments, consistent with the observed AIE behavior. Consequently, this study clearly demonstrates the structure-property relationship between the π-bridge structure and photophysical properties, showing that the thiophene bridge provides precise control over ICT strength, emission wavelength, and color tunability. These findings demonstrate that π-bridge engineering is an effective.