Mixed Chloride/Phosphine Complexes of the Dirhenium Core. 10. Redox Reactions of an Edge-Sharing Dirhenium(III) Non-metal−Metal-Bonded Complex, Re₂(μ-Cl)₂Cl₄(PMe₃)₄

Reduction and oxidation reactions of the dirhenium(III) non-metal−metal-bonded edge-sharing complex, Re₂(μ-Cl)₂Cl₄(PMe₃)₄ (1), have been studied. Several new mono- and dinuclear rhenium compounds have been isolated and structurally characterized in the course of this study. Reductions of 1 with 1 and 2 equiv of KC₈ result in an unusual face-sharing complex having an Re₂⁵⁺ core, Re₂(μ-Cl)₃Cl₂(PMe₃)₄ (2), and a triply bonded Re^II compound, 1,2,7,8-Re₂Cl₄(PMe₃)₄ (3), respectively. Two-electron reduction of 1 in the presence of tetrabutylammonium chloride affords a new triply bonded complex of the Re₂⁴⁺ core, [Buⁿ₄N][1,2,7-Re₂Cl₅(PMe₃)₃] (4). Oxidation of 1 with NOBF₄ yields a Re^IV mononuclear compound, trans-ReCl₄(PMe₃)₂ (5). Two isomers of the monomeric Re^III anion, [ReCl₄(PMe₃)₂]^- (6, 7), have been isolated as side products. The crystal structures of compounds 2 and 4−7 have been determined by X-ray crystallography. The Re−Re distance in the face-sharing complex 2 of 2.686(1) Å is relatively short. The metal−metal bond length in anion 4 of 2.2354(7) Å is consistent with the usual values for the triply bonded Re₂⁴⁺ core compounds. In addition, a cis arrangement of trimethylphosphine ligands in the starting material 1 is retained upon reduction in the dinuclear products 2−4.