Author, as appears in the article.: Saureu, Sergi; de Graaf, Coen;
Department: Química Física i Inorgànica
URV's Author/s: De Graaf, Cornelis
Keywords: Transition-metal complexes Transition Temperature State energetics Spectroscopy Iron(iii) compounds Inorganic chemistry Fe(phen)(2)(ncs)(2) Electronic-structure Electronic structure Dynamics Basis-sets 2nd-order perturbation-theory
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-field states as intermediates in this process. The B3LYP* functional has previously shown its ability to accurately describe (light-induced) spin-crossover in Fe(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 multiconfigurational 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 π-π* 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 efficiency encountered in experiments.
Thematic Areas: Química Physics, atomic, molecular & chemical Physics and astronomy (miscellaneous) Physics and astronomy (all) Physical and theoretical chemistry Odontología Medicina ii Medicina i Materiais Matemática / probabilidade e estatística Interdisciplinar Geociências General physics and astronomy General medicine Farmacia Ensino Engenharias iv Engenharias iii Engenharias ii Ciências biológicas ii Ciências biológicas i Ciências ambientais Ciências agrárias i Ciência de alimentos Ciência da computação Chemistry, physical Biotecnología Biodiversidade Astronomia / física
licence for use: https://creativecommons.org/licenses/by/3.0/es/
Author's mail: coen.degraaf@urv.cat
Author identifier: 0000-0001-8114-6658
Record's date: 2024-09-07
Papper version: info:eu-repo/semantics/submittedVersion
Licence document URL: https://repositori.urv.cat/ca/proteccio-de-dades/
Papper original source: Physical Chemistry Chemical Physics. 18 (2): 1233-1244
APA: Saureu, Sergi; de Graaf, Coen; (2016). TD-DFT study of the light-induced spin crossover of Fe(III) complexes. Physical Chemistry Chemical Physics, 18(2), 1233-1244. DOI: 10.1039/c5cp06620d
Entity: Universitat Rovira i Virgili
Journal publication year: 2016
Publication Type: Journal Publications
Repositori URV