Insights into Structure–Property Relationships in Quinoline–Based D–π–A Systems: A Synthetic and Computational Approach
6 affiliations
- 1Laboratorio de Radicales Libres y Antioxidantes, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Av. Libertador Bernardo O’Higgins 1058, Santiago 8330111, Chile
- 2Grupo de Investigación IDEFARMA, Departamento de Regencia y Farmacia, Facultad Ciencias de la Salud, Universidad de Córdoba, Monteria 230002, Colombia
- 3Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad de Concepción, Concepcion 4130000, Chile
- 4Organic and Biomedical Chemistry Research Group, Molecular Biology Research Laboratory, Faculty of Basic Science, Universidad Del Atlantico, Barranquilla 081007, Colombia
- 5Laboratorio de Síntesis y Reactividad de Compuestos Orgánicos, Facultad de Ciencias Exactas, Departamento de Ciencias Químicas, Universidad Andrés Bello, Santiago 8370146, Chile
- 6Departamento de Química Orgánica, Facultad de Química y de Farmacia, Escuela de Química, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile
Abstract
In this study, four quinoline–based chromophores (EP01–EP04) with distinct π–conjugated architectures were studied to understand how molecular connectivity influences their electronic structure and nonlinear optical properties. Experimental characterization was combined with DFT and TD–DFT calculations to relate molecular structure to UV–Vis absorption, frontier–orbital distribution, and calculated electronic response. EP01, which contains a vinylene bridge connecting quinoline to an alkoxy–substituted aromatic ring, exhibited the smallest HOMO–LUMO gap in the series (5.65 eV) and the most red–shifted experimental absorption in methanol (353 nm). In comparison, the principal absorption maximum of EP02 occurred at 265 nm. The results for EP03 and EP04 showed that band position and intensity depend not only on the HOMO–LUMO gap but also on the orbitals involved in each transition. The calculated solvent effect on the most intense transitions was limited, with shifts of 2–7 nm between toluene and water. EP01 also exhibited the largest calculated first and second hyperpolarizabilities, approximately 2.58 and 2.92 times those of EP02, respectively. Together, these findings show that connecting the aromatic fragments through a continuous π–pathway favors the optical response of these derivatives and provides structural guidance for designing new quinoline–based chromophores.
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BibTeX
@article{rojaspena2026insights,
title = {{Insights into Structure–Property Relationships in Quinoline–Based D–π–A Systems: A Synthetic and Computational Approach}},
author = {Cristian Rojas-Peña and Roger Espinosa-Saez and Camilo Guzmán-Terán and Claudio A. Jiménez and Angie Ortega Villadiego and Jairo Enrique Salazar and Dayanna Orosco and Yeray A. Rodríguez-Núñez and Jhon J. López and Carlos Mario Meléndez and Efraín Polo-Cuadrado},
journal = {Molecules},
year = {2026},
month = oct,
doi = {10.3390/molecules31203753},
url = {https://www.mdpi.com/1420-3049/31/20/3753},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Insights into Structure–Property Relationships in Quinoline–Based D–π–A Systems: A Synthetic and Computational Approach
AU - Cristian Rojas-Peña
AU - Roger Espinosa-Saez
AU - Camilo Guzmán-Terán
AU - Claudio A. Jiménez
AU - Angie Ortega Villadiego
AU - Jairo Enrique Salazar
AU - Dayanna Orosco
AU - Yeray A. Rodríguez-Núñez
AU - Jhon J. López
AU - Carlos Mario Meléndez
AU - Efraín Polo-Cuadrado
PY - 2026
DA - 2026/10/01
JO - Molecules
DO - 10.3390/molecules31203753
UR - https://www.mdpi.com/1420-3049/31/20/3753
AB - In this study, four quinoline–based chromophores (EP01–EP04) with distinct π–conjugated architectures were studied to understand how molecular connectivity influences their electronic structure and nonlinear optical properties. Experimental characterization was combined with DFT and TD–DFT calculations to relate molecular structure to UV–Vis absorption, frontier–orbital distribution, and calculated electronic response. EP01, which contains a vinylene bridge connecting quinoline to an alkoxy–substituted aromatic ring, exhibited the smallest HOMO–LUMO gap in the series (5.65 eV) and the most red–shifted experimental absorption in methanol (353 nm). In comparison, the principal absorption maximum of EP02 occurred at 265 nm. The results for EP03 and EP04 showed that band position and intensity depend not only on the HOMO–LUMO gap but also on the orbitals involved in each transition. The calculated solvent effect on the most intense transitions was limited, with shifts of 2–7 nm between toluene and water. EP01 also exhibited the largest calculated first and second hyperpolarizabilities, approximately 2.58 and 2.92 times those of EP02, respectively. Together, these findings show that connecting the aromatic fragments through a continuous π–pathway favors the optical response of these derivatives and provides structural guidance for designing new quinoline–based chromophores.
SN - 1420-3049
ER -