Two-Photon Absorption and Multiphoton Excited Fluorescence of Acetamide-Chalcone Derivatives: The Role of Dimethylamine Group on the Nonlinear Optical and Photophysical Properties
André Gasparotto Pelosi,
Eli Silveira-Alves,
Leandro Henrique Zucolotto Cocca,
João Victor Valverde,
Guilherme Roberto Oliveira,
Daniel Luiz da Silva,
Leonardo De Boni,
Pablo José Gonçalves,
Cleber Renato Mendonca
Affiliations
André Gasparotto Pelosi
São Carlos Institute of Physics, University of São Paulo, São Carlos 13566-590, SP, Brazil
Eli Silveira-Alves
Institute of Chemistry, Federal University of Goiás, Goiânia 74690-900, GO, Brazil
Leandro Henrique Zucolotto Cocca
São Carlos Institute of Physics, University of São Paulo, São Carlos 13566-590, SP, Brazil
João Victor Valverde
São Carlos Institute of Physics, University of São Paulo, São Carlos 13566-590, SP, Brazil
Guilherme Roberto Oliveira
Institute of Chemistry, Federal University of Goiás, Goiânia 74690-900, GO, Brazil
Daniel Luiz da Silva
Department of Natural Sciences, Mathematics and Education, Federal University of São Carlos, Araras 13604-900, SP, Brazil
Leonardo De Boni
São Carlos Institute of Physics, University of São Paulo, São Carlos 13566-590, SP, Brazil
Pablo José Gonçalves
Institute of Chemistry, Federal University of Goiás, Goiânia 74690-900, GO, Brazil
Cleber Renato Mendonca
São Carlos Institute of Physics, University of São Paulo, São Carlos 13566-590, SP, Brazil
This work studied the effect of different electron-withdrawing and electron-donating groups on the linear and nonlinear optical properties of acetamide-chalcone derivatives. The results showed that the addition of the dimethylamine group led to a large fluorescence emission (71% of fluorescence quantum yield in DMSO solution) that can be triggered by two and three-photon excitations, which is essential for biological applications. Furthermore, dimethylamine also red-shifts the lower energy state by approximately 90 nm, increasing the two-photon absorption cross-section of the lower energy band by more than 100% compared with the other studied compounds. All compounds presented two-electronic states observed through one and two-photon absorption spectroscopy and confirmed by Quantum Chemistry Calculations (QCCs). QCC results were also used to model the experimental two-photon absorption cross-sectional spectrum by the Sum-Over-States (SOS) approach, revealing a dependence between the coupling of the ground state with the first excited state and the transition dipole moment between these states.
