title: Diarylethene-containing carbon-rich ruthenium organometallics: tuning of electrochromism.
abstract: The association of a dithienylethene (DTE) system with ruthenium carbon-rich systems allows reaching sophisticated and efficient light- and electro-triggered multifunctional switches R-[Ru]-C≡C-DTE-C≡C-[Ru]-R, featuring multicolor electrochromism and electrochemical cyclization at remarkably low voltage. The spin density on the DTE ligand and the energetic stabilization of the system upon oxidation could be manipulated to influence the closing event, owing to the noninnocent behavior of carbon-rich ligands in the redox processes. A combination of spectroscopic (UV-vis-NIR-IR and EPR) and electrochemical studies, with the help of quantum chemical calculations, demonstrates that one can control and get a deeper understanding of the electrochemical ring closure with a slight modification of ligands remote from the DTE unit. This electrochemical cyclization was established to occur in the second oxidized state (EEC mechanism), and the kinetic rate constant in solution was measured. Importantly, these complexes provide an unprecedented experimental means to directly probe the remarkable efficiency of electronic (spin) delocalization between two trans carbon-rich ligands through a metal atom, in full agreement with the theoretical predictions. In addition, when no cyclization occurs upon oxidation, we could achieve a redox-triggered magnetic switch.
authors.affiliation: Institut des Sciences Chimiques de Rennes, UMR no. 6226 CNRS-Université de Rennes 1 , Campus de Beaulieu, F-35042, Rennes, Cedex, France.
authors.forename: Yifei
authors.initials: Y
authors.lastname: Liu
authors.forename: Cheikh Mbacké
authors.initials: CM
authors.lastname: Ndiaye
authors.forename: Corinne
authors.initials: C
authors.lastname: Lagrost
authors.forename: Karine
authors.initials: K
authors.lastname: Costuas
authors.forename: Sylvie
authors.initials: S
authors.lastname: Choua
authors.forename: Philippe
authors.initials: P
authors.lastname: Turek
authors.forename: Lucie
authors.initials: L
authors.lastname: Norel
authors.forename: Stéphane
authors.initials: S
authors.lastname: Rigaut