Influence of peripherical modifications in linear and nonlinear photophysical properties of imidazo[4,5-b]pyridine derivatives

Author(s)

Marbello, O. D. ; Pelosi, A. G. ; Cocca, Leandro H. Z. ; Valverde, J. V. P. ; Piguel, S. ; De Boni, L. ; Mendonca, C. R.

• Document type: Journal article
• Source: JOURNAL OF MOLECULAR LIQUIDS; v. 390, p. 9-pg., 2023-09-21.

Abstract

This study reports a wide study on linear and nonlinear optical properties of six imidazo[4,5-b]pyridines derivates. The compounds are coupled with a series of peripheral groups forming different dipolar structures (D pi A and A pi 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 -pi -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. (AU)

• FAPESP's process: 18/11283-7 - Nonlinear photonics: spectroscopy and advanced processing of materials
• Grantee: Cleber Renato Mendonça
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 15/20032-0 - Study on Nonlinear and Charge Transport Properties of Multi-branched Molecules via Quantum Chemical Methods.
• Grantee: Daniel Luiz da Silva
• Support Opportunities: Regular Research Grants
• FAPESP's process: 16/20886-1 - Ultrafast nonlinear optical spectroscopy: Transient Absorption and optical Kerr Gate with polarization control
• Grantee: Leonardo de Boni
• Support Opportunities: Regular Research Grants
• FAPESP's process: 20/08715-2 - Fabrication of polymeric micro-resonators with nanodiamonds for quantum information technologies
• Grantee: Filipe Assis Couto
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 11/12399-0 - Femtosecond pulses applied to nonlinear optics: spectroscopy, pulse shaping and microfabrication
• Grantee: Cleber Renato Mendonça
• Support Opportunities: Research Projects - Thematic Grants