Syntheses and Structures of Ruthenium Complexes Containing a Ru-H-Tl Three-Center-Two-Electron Bond

Treatment of CpRuH(PP) (PP=dppm, dppe) with TlPF₆ produced [CpRu(H)(Tl)(PP)]PF₆ . X-ray diffraction and computational studies suggest that the complexes contain a Ru-H-Tl 3c-2e bond and can be viewed as the first σ-complexes of period 6 main-group hydrides [CpRu{η² -(H-Tl)}(PP)]PF₆ or [Tl{η² -H-RuCp(PP)}]PF₆ . The complexes can be stored as a solid at room temperature for days without appreciable decomposition, but are unstable in solution and evolved to the trimetallic complexes [{CpRu(PP)}₂ (μ-Tl)]PF₆ .