nfluence of electron-withdrawing groups in two-photon absorption of imidazopyridines derivative

Autor(es)

Pelosi, Andre Gasparotto ^[1] ; Zucolotto Cocca, Leandro Henrique ^[1] ; Abegao, Luis M. G. ^[2] ; Sciuti, Lucas Fiocco ^[1] ; Piguel, Sandrine ^{[3, 4]} ; De Boni, Leonardo ^[1] ; Mendonca, Cleber R. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Fis Sao Carlos, CP 369, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Fed Goias, Inst Fis, Grp Foton, BR-74690900 Goiania, Go - Brazil

^[3] Univ Paris Saclay, CNRS UMR 9187, INSERM U1196 Chim & Modelisat Biol Canc, F-91405 Orsay - France

^[4] Inst Curie, INSERM U1196 Chim & Modelisat Biol Canc, CNRS UMR 9187, F-91405 Orsay - France

• Tipo de documento: Artigo Científico
• Fonte: DYES AND PIGMENTS; v. 198, FEB 2022.
• Citações Web of Science: 0

Resumo

This work investigates the influence of different electron-withdrawing groups (Cl, Br, fluorobenzonitrile), on the two-photon absorption cross-section of six imidazo{[}4,5-b]pyridine derivatives. The two-photon absorption crosssection spectra were obtained by ultra-fast Z-scan technique from 470 nm up to 700 nm. The Sum-Over-States approach was applied to model the two-photon absorption spectra, using a three-level energy system. Photophysical properties, such as transition dipole moment, the difference of permanent dipole moments, and anisotropy coefficient were determined through the analysis of one-photon absorption spectra, solvatochromism, and fluorescence anisotropy, respectively. Besides, the excited state absorption spectra were measured through ultra-fast transient absorption, allowing the excited state lifetime and spectral position determination. Twophoton absorption cross-sections of about 160 GM were observed when two electron-withdrawing groups are linked to the imidazo{[}4,5-b]pyridine core, elucidating a path to achieve high optical nonlinearities in imidazopyridine derivatives. Furthermore, a increase in the two-photon cross-section was observed when chloride is linked at the C-6 position (90 GM) instead of the C-5 position (50 GM), which is related to the proximity of a higher excited state. (AU)

• Processo FAPESP: 18/11283-7 - Fotônica não linear: espectroscopia e processamento avançado de materiais
• Beneficiário: Cleber Renato Mendonça
• Modalidade de apoio: Auxílio à Pesquisa - Temático