Cooperative Bond Activation Reactions with Ruthenium Carbene Complex PhSO₂(Ph₂PNSiMe₃)CRu(p‑cymene): RuC and N–Si Bond Reactivity

The synthesis of ruthenium carbene complex PhSO₂(Ph₂PNSiMe₃)­CRu­(p-cymene) (3) and its application in cooperative bond activation reactions were studied. Compound 3 is accessible via salt metathesis using the dilithium methandiide ligand or alternatively via dehydrohalogenation of the corresponding chlorido complex 2. The carbene complex was studied by X-ray crystallography, multielement NMR spectroscopy, and DFT studies, all of which confirm the presence of a RuC double bond. The polarization of the RuC bond is less pronounced than in an analogous carbene complex with a thiophosphoryl instead of the iminophosphoryl moiety. This should be beneficial for realizing reversible activation processes by the addition of element-hydrogen bonds across the RuC double bond. Accordingly, 3 is more stable and the RuC linkage less reactive in the activation of aromatic alcohols and elemental dihydrogen, showing reversible processes and longer reaction times. Despite the selective addition of dihydrogen across the Ru–C bond, the activation of O–H bonds was accompanied by hydrolysis of the N–Si linkage. The reaction of 3 with water led to the hydrolysis of the N–Si bond as well as protonative cleavage of the central P–C bond in the ligand backbone, thus resulting in the formation of an unusual dinuclear ruthenium–imido complex.