Optical induced valence tautomeric interconversion in cobalt dioxolene complexes

Alessandra Beni (1) , Chiara Carbonera (2) , Andrea Dei (1) , Jean-François Létard (2) , Roberto Righini (3) , Claudio Sangregorio (1) , Lorenzo Sorace (1)

1 Dipartimento di Chimica
2 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
3 LENS - European Laboratory for Non-Linear Spectroscopy

The discovery that a number of cobalt-dioxolene complexes undergo photoswitchable behavior was reported in the recent past. This phenomenon is always associated with valence tautomeric interconversion processes involving low-spin cobalt(III) and high-spin cobalt(II) species. Herein is stressed the strong formal correlation existing between these processes and the LIESST (Light-Induced Excited Spin State Trapping) effect shown by several iron(II) complexes undergoing spin crossover interconversion. The dynamics of the relaxation of the photoinduced metastable species to the ground state is discussed in terms of non-adiabatic processes within the Jortner theory of radiationless multiphonon relaxation.

Mots clés: Cobalt; Valence tautomerism; Redox properties; Isomerism; Photochromism; Photoinduction; Photomagnetism; Semiquinone; Radical ligand

Domaines: Matériaux

Alessandra Beni, Chiara Carbonera, Andrea Dei, Jean-François Létard, Roberto Righini, et al.. Optical induced valence tautomeric interconversion in cobalt dioxolene complexes. Journal of the Brazilian Chemical Society, 2006, 17 (8), pp.1522-1533. ⟨10.1590/S0103-50532006000800007⟩. ⟨hal-00125027⟩