Autor segons l'article: Casellas, Josep; Alcover-Fortuny, Gerard; de Graaf, Coen; Reguero, Mar
Departament: Química Física i Inorgànica
e-ISSN: 1996-1944
Autor/s de la URV: De Graaf, Cornelis / Reguero de la Poza, Maria del Mar
Paraules clau: Thermal relicts; Reaction mechanism; Photoisomerization; Photochromism; Photochemistry; Phenylazopyridine; Pannonian region; Mechanism of reaction; Holocene thermal maximum; Excited states; Disjunction; Casscf/caspt2; photoisomerization; photochromism; phenylazopyridine; casscf/caspt2
Resum: Azo compounds are organic photochromic systems that have the possibility of switching between cis and trans isomers under irradiation. The different photochemical properties of these isomers make azo compounds into good light-triggered switches, and their significantly different geometries make them very interesting as components in molecular engines or mechanical switches. For instance, azo ligands are used in coordination complexes to trigger photoresponsive properties. The light-induced trans-to-cis isomerization of phenylazopyridine (PAPy) plays a fundamental role in the room-temperature switchable spin crossover of Ni-porphyrin derivatives. In this work, we present a computational study developed at the SA-CASSCF/CASPT2 level (State Averaged Complete Active Space Self Consistent Field/CAS second order Perturbation Theory) to elucidate the mechanism, up to now unknown, of the cis-trans photoisomerization of 3-PAPy. We have analyzed the possible reaction pathways along its lowest excited states, generated by excitation of one or two electrons from the lone pairs of the N atoms of the azo group (nazo pi*2 and nazo2 pi*2 states), from a pi delocalized molecular orbital (pi pi* state), or from the lone pair of the N atom of the pyridine moiety (npy pi* state). Our results show that the mechanism proceeds mainly along the rotation coordinate in both the nazo pi* and pi pi* excited states, although the nazo2 pi*2 state can also be populated temporarily, whilethe npy pi* does not intervene in the reaction. For rotationally constrained systems, accessible paths to reach the cis minimum along planar geometries have also been located, again on the nazo pi* and pi pi* potential energy surfaces, while the nazo 2 pi*2 and npy pi* states are not involved in the reaction. The relative energies of the different paths differ from those found for azobenzene in a previous work, so our results predict some differences between the reactivities of both compounds.
Àrees temàtiques: Química; Odontología; Medicina veterinaria; Medicina i; Materials science, multidisciplinary; Materiais; Interdisciplinar; General materials science; Engenharias iv; Engenharias iii; Engenharias ii; Engenharias i; Condensed matter physics; Ciências biológicas ii; Ciências biológicas i; Ciências agrárias i; Ciência de alimentos; Ciência da computação; Biotecnología; Astronomia / física; Arquitetura, urbanismo e design
Accès a la llicència d'ús: https://creativecommons.org/licenses/by/3.0/es/
ISSN: 19961944
Adreça de correu electrònic de l'autor: coen.degraaf@urv.cat; mar.reguero@urv.cat
Data d'alta del registre: 2025-01-28
Volum de revista: 10
Versió de l'article dipositat: info:eu-repo/semantics/publishedVersion
Enllaç font original: https://www.mdpi.com/1996-1944/10/12/1342
URL Document de llicència: https://repositori.urv.cat/ca/proteccio-de-dades/
Referència a l'article segons font original: Materials. 10 (12): 1342-
Referència de l'ítem segons les normes APA: Casellas, Josep; Alcover-Fortuny, Gerard; de Graaf, Coen; Reguero, Mar (2017). Phenylazopyridine as switch in photochemical reactions. A detailed computational description of the mechanism of its Photoisomerization. Materials, 10(12), 1342-. DOI: 10.3390/ma10121342
DOI de l'article: 10.3390/ma10121342
Entitat: Universitat Rovira i Virgili
Any de publicació de la revista: 2017
Tipus de publicació: Journal Publications
Repositori URV