Electrochemical studies on neutral triple-bridged di-ruthenium compounds.

Reactions of Benzyne−Nickel(0) Complexes with Thioalkynes: Preparation and Coordination of Polydentate Thioethers Containing a 2,3-Naphthylene Backbone

“…The first oxidation, resulting in a Ru II ,Ru III mixed-valence species, is understood to be centered more on the ruthenium bearing the terminal chloride, whereas the second one is more on the Ru(L)(PR 3 ) 2 site or, presumably in the case of 6, the ruthenium chelated by the dithioether group. 42,43,47 The E°values reported for those Ru 2 Cl 4 L 5 complexes depend on the nature of the auxiliary phosphines, but are similar to those of 6; for example, the first oxidation takes place at 0.43 V for [(Et 2 PhP) 3 Ru-(µ-Cl) 3 RuCl(PPhEt 2 ) 2 ] ( 14) (vs Ag-AgCl), 43,46 0.71 V for [(Ph 2 MeP) 3 Ru(µ-Cl) 3 RuCl(PMePh 2 ) 2 ], 43 0.52 V for [(Ph 3 P) 2 (CO)Ru(µ-Cl) 3 RuCl(PPh 3 ) 2 ] (15), 42 and an estimated value of ca. 0.65 V for [(Ph 3 P) 3 Ru(µ-Cl) 3 RuCl-(PPh 3 ) 2 ] ( 16), 48 while the related cationic species [(R 3 P) 3 -Ru(µ-Cl) 3 Ru(PR 3 ) 3 ] + have higher oxidation potentials, e.g., 1.28 V for [(Ph 3 P) 3 Ru(µ-Cl) 3 Ru(PPh 3 ) 3 ] + .…”

“…Ruthenium dinuclear complexes linked by three chloro bridges are quite common. Species with two unsymmetrical terminal faces have been described, but these compounds have generally been obtained with phosphines or arsines as auxiliary ligands; ,− complex 6 is the first example of such a ruthenium complex incorporating thioether ligands. These complexes, spanning the oxidation states II,II, II,III, and III,III, have been studied extensively for their spectroelectrochemical behaviors, as the oxidation of the Ru II ,Ru II complex to a mixed-valence species Ru II ,Ru III is usually accompanied by the generation of an intense color.…”