TD-DFT Study of the Light-induced Spin Crossover of Fe(III) Complexes

De Graaf, C. ; Saure, S.

Belongs to PC:SerieArticles collection

TITLE:

TD-DFT Study of the Light-induced Spin Crossover of Fe(III) Complexes - PC:3125

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https://hdl.handle.net/20.500.11797/PC3125

URV's Author/s:	DE GRAAF , CORNELIS; Saure, S.
Author, as appears in the article.:	De Graaf, C. ; Saure, S.
Author identifier:	0000-0001-8114-6658;
Journal publication year:	2016
Publication Type:	Article
ISSN:	1463-9076
Abstract:	Two light-induced spin-crossover Fe(III) compounds have been studied with time-dependent density functional theory (TD-DFT) to investigate the deactivation mechanism and the role of the ligand-eld states as intermediates in this process. The B3LYP* functional has previously shown its ability to accurately describe (light-induced) spin-crossover inFe(II) complexes. Here, we establish its performance for Fe(III) systems using [Fe(qsal)2]+(Hqsal=2-[(8-quinolinylimino)methyl] phenol) and [Fe(pap)2]+ (Hpap=2-(2-pyridylmethyleneamino)phenol) as test cases comparing the B3LYP* results to experimental information and to multicongurational wave function results. In addition to rather accurate high spin (HS) and low spin (LS) state geometries, B3LYP* also predicts ligand-to-metal charge transfer (LMCT) states with large oscillator strength in the energy range where the UV-VIS spectrum shows an intense absorption band, whereas optically allowed - excitations on the ligands were calculated at higher energy. Subsequently, we have generated a two-dimensional potential energy surface of the HS and LS states varying the Fe-N and Fe-O distances. LMCT and metal centered (MC) excited states were followed along the approximate minimal energy path that connects the minima of the HS and LS on this surface. The 2LMCT state has a minimum in the same region as the initial LS state, where we also observe a crossing with the intermediate spin (IS) state. Upon the expansion of the coordination sphere of the Fe(III) ion, the IS state crosses with the HS state and further expansion of the coordination sphere leads to the excited spin state trapping as observed in experiment. The calculation of the intersystem crossing rates reveals that the deactivation from 2LMCT!IS!HS competes with the 2LMCT!IS!LS pathway, in line with the low eciency encountered in experiments.
Article's DOI:	10.1039/C5CP06620D
Link to the original source:	http://pubs.rsc.org/en/content/articlelanding/2016/cp/c5cp06620d#!divAbstract
Paper version:	info:eu-repo/semantics/submittedVersion
licence for use:	https://creativecommons.org/licenses/by/3.0/es/
Department:	Química Física i Inorgànica
Research group:	Química Quàntica
Licence document URL:	https://repositori.urv.cat/ca/proteccio-de-dades/
Thematic Areas:	Chemistry
Keywords:	TD-DFT Fe(III) Complexes Light induced spin cross over
Entity:	Universitat Rovira i Virgili
Record's date:	2018-02-28
First page:	1233
Last page:	1244

Description:	Two light-induced spin-crossover Fe(III) compounds have been studied with time-dependent density functional theory (TD-DFT) to investigate the deactivation mechanism and the role of the ligand-eld states as intermediates in this process. The B3LYP* functional has previously shown its ability to accurately describe (light-induced) spin-crossover inFe(II) complexes. Here, we establish its performance for Fe(III) systems using [Fe(qsal)2]+(Hqsal=2-[(8-quinolinylimino)methyl] phenol) and [Fe(pap)2]+ (Hpap=2-(2-pyridylmethyleneamino)phenol) as test cases comparing the B3LYP* results to experimental information and to multicongurational wave function results. In addition to rather accurate high spin (HS) and low spin (LS) state geometries, B3LYP* also predicts ligand-to-metal charge transfer (LMCT) states with large oscillator strength in the energy range where the UV-VIS spectrum shows an intense absorption band, whereas optically allowed - excitations on the ligands were calculated at higher energy. Subsequently, we have generated a two-dimensional potential energy surface of the HS and LS states varying the Fe-N and Fe-O distances. LMCT and metal centered (MC) excited states were followed along the approximate minimal energy path that connects the minima of the HS and LS on this surface. The 2LMCT state has a minimum in the same region as the initial LS state, where we also observe a crossing with the intermediate spin (IS) state. Upon the expansion of the coordination sphere of the Fe(III) ion, the IS state crosses with the HS state and further expansion of the coordination sphere leads to the excited spin state trapping as observed in experiment. The calculation of the intersystem crossing rates reveals that the deactivation from 2LMCT!IS!HS competes with the 2LMCT!IS!LS
Title:	TD-DFT Study of the Light-induced Spin Crossover of Fe(III) Complexes
Coverage:	Anglès
Type:	post-print Article Artículo Article info:eu-repo/semantics/submittedVersion
Contributor:	Química Quàntica Química Física i Inorgànica Universitat Rovira i Virgili
Subject:	Funcional de densitat, Teoria del Ferro--Compostos TD-DFT Fe(III) Complexes Light induced spin cross over Química Química Chemistry 1463-9076
Date:	2016
Format:	7086 kb
Creator:	De Graaf, C. Saure, S.
Rights:	info:eu-repo/semantics/openAccess

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