Influence of electron-withdrawing groups in two-photon absorption of imidazopyridines derivatives.
PELOSI, André Gasparotto; COCCA, Leandro Henrique Zucolotto; ABEGÃO, Luis Miguel Gomes; SCIUTI, Lucas Fiocco; PIGUEL, Sandrini; DE BONI, Leonardo; MENDONÇA, Cleber Renato.
PELOSI, André Gasparotto; COCCA, Leandro Henrique Zucolotto; ABEGÃO, Luis Miguel Gomes; SCIUTI, Lucas Fiocco; PIGUEL, Sandrini; DE BONI, Leonardo; MENDONÇA, Cleber Renato.
Abstract: 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 cross- section 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. Photo- physical 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. Two- photon 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 imida- zopyridine 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.
@article={003054243,author = {PELOSI, André Gasparotto; COCCA, Leandro Henrique Zucolotto; ABEGÃO, Luis Miguel Gomes; SCIUTI, Lucas Fiocco; PIGUEL, Sandrini; DE BONI, Leonardo; MENDONÇA, Cleber Renato.},title={Influence of electron-withdrawing groups in two-photon absorption of imidazopyridines derivatives},journal={Dyes and Pigments},note={v. 198, p. 109972-1-109972-7},year={2022}}