On the spin-state dependence of redox potentials of spin crossover complexes

Isabelle M. Dixon (1) , Sylvain Rat (2) , Alix Sournia-Saquet (2) , Gábor Molnár (2) , Lionel Salmon (2) , Azzedine Bousseksou (2)

1 LCPQ - Laboratoire de Chimie et Physique Quantiques
2 LCC - Laboratoire de chimie de coordination

Resistance switching properties of nanoscale junctions of spin crossover molecules have received recently much interest. In many cases, this property has been traced back to the variation of molecular orbital energies upon spin transition. However, one can also expect a substantial reorganization of the molecular structure due to charge localization, which calls for a better understanding of the relationship between the redox potential and the spin state of the molecule. To investigate this issue, we carried out a detailed density functional theory and variable temperature cyclic voltammetry investigation of the benchmark compound [Fe(HB(1,2,4-triazol-1-yl)3)2] in solution. We show that, for a correct thermodynamical picture, it is necessary to take into account the charge transfer-induced electronic and structural reorganization as well as spin equilibria in the oxidized and reduced species.

Mots clés: Redox reactions; Oxidation; Quantum mechanics; Mathematical methods; Electrochemical reduction

Domaines: Chimie

Isabelle M. Dixon, Sylvain Rat, Alix Sournia-Saquet, Gábor Molnár, Lionel Salmon, et al.. On the spin-state dependence of redox potentials of spin crossover complexes. Inorganic Chemistry, 2020, 59 (24), pp.18402-18406. ⟨10.1021/acs.inorgchem.0c03043⟩. ⟨hal-03102204⟩