μ-Disulfido complexes of ruthenium(III) 1,1′-dithiolate [{(Me3tacn)Ru}2(κ2-S2COR)(κ2-S2C = O)(μ-S2)]PF6 (Me3tacn = 1,4,7-trimethyl-1,4,7-triazacyclononane; R = alkyl)

Treatment of [(Me3tacn)RuCl3·H2O] with equivalent of sodium dialkyldithiocarbamate in the presence of KPF6 afforded the mononuclear species [(Me3tacn)RuIII(κ2-S2CNR2)Cl]PF6 (Me3tacn = 1,4,7-trimethyl-1,4,7-triazacyclononane; R = Me 1, Et 2, nPr 3, iPr 4). The similar reactions using O-alkyldithiocarbonate gave dinuclear species [{(Me3tacn)RuIII}2(κ2-S2COR)(κ2-S2C = O)(μ-S2)]PF6 (R = Me 5, Et 6, nPr 7, iPr 8), in which SS bond formed and partial conversion of η2-dithioxanthate to η2-dithiocarbonate occurred. The crystal structures of 2, 3, 4, 6, and 8 have been determined. The complexes have been characterized by infrared, UV–vis-NIR spectroscopies and mass spectrometry, and their electrochemical properties were also investigated. The dinuclear complexes (6–8) showed absorptions in the near-infrared (NIR) region around 1700 nm. Density functional theory calculation was performed on complexes 6 and 8 to explain the NIR performance. The visible-light-induced catalytic properties of dinuclear complexes 5–8 for H2 evolution by water splitting were explored in the paper.