Synthesis and characterization of dithia[3.3]paracyclophane-bridged binuclear ruthenium vinyl and alkynyl complexes

The dithia[3.3]paracyclophane-bridged bimetallic ruthenium alkynyl and vinyl complexes {Cp*(dppe)RuC≡C}2(μ-dithia[3.3]paracyclophane) (8) and {(PMe3)3(CO)ClRuCH═CH}2(μ-dithia[3.3]paracyclophane) (9) have been prepared and, in the case of 8, structurally characterized. Compounds 8 and 9 each undergo two consecutive one-electron-oxidation processes, with supporting investigations conducted using IR and UV/vis/near-IR spectroelectrochemical methods establishing the redox-noninnocent character of the dithia[3.3]paracyclophane bridge unit in both 8 and 9. Both [8]+ and [9]+ exhibit multiple transitions in the near-IR region, which have been assigned with the aid of DFT calculations to combinations of MLCT and intraligand transitions and transitions involving the donor sulfur atoms within the cyclophane scaffold to the partially occupied orbital located on the diethynyl- or divinylphenylene portion of the bridging cyclophane.