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

Treatment of CpRuH(PP) (PP=dppm, dppe) with TlPF 6 produced [CpRu(H)(Tl)(PP)]PF 6 . 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{η 2 ‐(H−Tl)}(PP)]PF 6 or [Tl{η 2 ‐H−RuCp(PP)}]PF 6 . 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)]PF 6 .