Autor según el artículo: Domenico Pirone; Nuno A. G. Bandeira; Bartosz Tylkowski; Emily Boswell; Regine Labeque; Ricard Garcia Valls; Marta Giamberini *

Departamento: Enginyeria Química

Autor/es de la URV: Garcia Valls, Ricard / Giamberini, Marta / Tylkowski, Bartosz

Palabras clave: Photoswitching uv-visible td-dft photoisomerization kinetics azobenzene azoaryls

Resumen: A molecular design approach was used to create asymmetrical visible light-triggered azo-derivatives that can be good candidates for polymer functionalization. The specific electron-donor substituted molecules were characterized and studied by means of NMR analyses and UV-visible spectroscopy, comparing the results with Time Dependent Density Functional (TD-DFT) calculations. A slow rate of isomerization (ki = 1.5 × 10-4 s-1) was discovered for 4-((2-hydroxy-5methylphenyl) diazenyl)-3-methoxybenzoic acid (AZO1). By methylating this moiety, it was possible to unlock the isomerization mechanism for the second molecule, methyl 3-methoxy-4-((2-methoxy-5-methylphenyl) diazenyl)benzoate (AZO2), reaching promising isomerization rates with visible light irradiation in different solvents. It was discovered that this rate was heightened by one order of magnitude (ki = 3.1 × 10-3 s-1) for AZO2. A computational analysis using density functional (DFT/PBE0) and wavefunction (QD-NEVPT2) methodologies provided insight into the photodynamics of these systems. Both molecules require excitation to the second (S2) excited state situated in the visible region to initiate the isomerization. Two classic mechanisms were considered, namely rotation and inversion, with the former being energetically more favorable. These azo-derivatives show potential that paves the way for future applications as building blocks of functional polymers. Likewise, they could be really effective for the modification of existing commercial polymers, thus transferring their stimuli responsive properties to polymeric bulky structures, converting them into smart materials.

Acceso a la licencia de uso: https://creativecommons.org/licenses/by/3.0/es/

Direcció de correo del autor: bartosz.tylkowski@urv.cat ricard.garcia@urv.cat marta.giamberini@urv.cat

Identificador del autor: 0000-0002-4163-0178 0000-0002-3945-0434 0000-0001-8278-3552

Fecha de alta del registro: 2023-09-30

Versión del articulo depositado: info:eu-repo/semantics/publishedVersion

Enlace a la fuente original: https://www.mdpi.com/2073-4360/12/5/1019

URL Documento de licencia: http://repositori.urv.cat/ca/proteccio-de-dades/

Referencia al articulo segun fuente origial: 12 (5): Article number 1019-

Referencia de l'ítem segons les normes APA: Domenico Pirone; Nuno A. G. Bandeira; Bartosz Tylkowski; Emily Boswell; Regine Labeque; Ricard Garcia Valls; Marta Giamberini * (2020). Contrasting photo-switching rates in Azobenzene derivatives: how the nature of the substituent plays a role. Polymers , 12(5), Article number 1019-. DOI: 10.3390/POLYM12051019

DOI del artículo: 10.3390/POLYM12051019

Entidad: Universitat Rovira i Virgili

Año de publicación de la revista: 2020

Tipo de publicación: Journal Publications