title: Ruthenium Carbon-Rich Complexes as Redox Switchable Metal Coupling Units.
abstract: With the help of EPR spectroscopy, we show that the diamagnetic [Ru(dppe)2(-C≡C-R)2] system sets up a magnetic coupling between two organic radicals R, i.e., two nitronyl nitroxide or two verdazyl units, which is stronger than that of related platinum organometallic systems. Surprisingly, further oxidation of the ruthenium redox-active metal coupling unit (MCU), which introduces an additional spin unit on the carbon-rich part, leads to the switching off of this interaction. On the contrary, in simpler complexes bearing only one of the organic radical ligands [C6H5-C≡C-Ru(dppe)2-C≡C-R], one-electron oxidation of the transition metal unit generates an interaction between the two spin carriers of comparable magnitude to that observed in the above corresponding neutral systems.
authors.affiliation: †UMR 6226 CNRS-Université de Rennes 1, Institut des Sciences Chimiques de Rennes, Campus de Beaulieu, F-35042, Rennes Cedex, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Di Piazza
authors.affiliation: †UMR 6226 CNRS-Université de Rennes 1, Institut des Sciences Chimiques de Rennes, Campus de Beaulieu, F-35042, Rennes Cedex, France.
authors.forename: Areej
authors.initials: A
authors.lastname: Merhi
authors.affiliation: †UMR 6226 CNRS-Université de Rennes 1, Institut des Sciences Chimiques de Rennes, Campus de Beaulieu, F-35042, Rennes Cedex, France.
authors.forename: Lucie
authors.initials: L
authors.lastname: Norel
authors.affiliation: ‡UMR 7177 CNRS-Université de Strasbourg, Institut de Chimie, 1 rue Blaise Pascal, BP 296 R8, F-67008 Strasbourg Cedex, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Choua
authors.affiliation: ‡UMR 7177 CNRS-Université de Strasbourg, Institut de Chimie, 1 rue Blaise Pascal, BP 296 R8, F-67008 Strasbourg Cedex, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Turek
authors.affiliation: †UMR 6226 CNRS-Université de Rennes 1, Institut des Sciences Chimiques de Rennes, Campus de Beaulieu, F-35042, Rennes Cedex, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Rigaut