Influence of peripherical modifications in linear and nonlinear photophysical properties of imidazo[4,5-b]pyridine derivatives.
OSPINA, Orlando David Marbello; PELOSI, André Gasparotto; COCCA, Leandro Henrique Zucolotto; VALVERDE, João Victor Pereira; PIGUEL, Sandrine; DE BONI, Leonardo; MENDONÇA, Cleber Renato.
OSPINA, Orlando David Marbello; PELOSI, André Gasparotto; COCCA, Leandro Henrique Zucolotto; VALVERDE, João Victor Pereira; PIGUEL, Sandrine; DE BONI, Leonardo; MENDONÇA, Cleber Renato.
Abstract: This study reports a wide study on linear and nonlinear optical properties of six imidazo[4,5-b]pyridines deri- vates. The compounds are coupled with a series of peripheral groups forming different dipolar structures (D-p-A and A-p-A). Photophysical parameters such as the anisotropy coefficient, transition dipole moment, and permanent dipole moment difference were determined using spectroscopic techniques. The two- photon absorption (2PA) cross-section spectra were obtained by the tunable femtosecond Z-scan technique. In addition, quantum chemical calculations and the Sum Over States (SOS) model for two energy levels were applied to support the experimental data. A single 2PA band, with 2PA cross-section varying from 70 to 110 GM, was observed in the 2PA cross-section spectra in the molecules with only acceptor groups. In addition, the presence of a second band around 660 nm and an increase in 2PA cross-section values (around 110 to 130 GM in the principal band) was observed for the molecules with a combination of the methoxy radical (OMe) with halogen groups (D-p-A structure). These results indicate that the non-centrosymetric A-Imp-D structures facilitate the polarizability and internal charge transfer processes, resulting in photophysical and two-photon absorption properties enhancement compared to A-Imp-A structures.
@article={003158259,author = {OSPINA, Orlando David Marbello; PELOSI, André Gasparotto; COCCA, Leandro Henrique Zucolotto; VALVERDE, João Victor Pereira; PIGUEL, Sandrine; DE BONI, Leonardo; MENDONÇA, Cleber Renato.},title={Influence of peripherical modifications in linear and nonlinear photophysical properties of imidazo[4,5-b]pyridine derivatives},journal={Journal of Molecular Liquids},note={v. 390, Part. 3, p. 123092-1-123092-9 + supplementary data},year={2023}}