Synthesis and Reactivity of Cyclopentadienyl Ruthenium(II) Complexes with Tris(alkylthio)benzenes: Transformation between Dinuclear and Sandwich-Type Complexes.

To explore the structural transformation of cyclopentadienyl ruthenium (CpRu) complexes in response to external stimuli, the reaction of [RuCp(MeCN)][X] (X = PF, (FSO)N [= FSA]) and tris(alkylthio)benzenes (1,3,5-CH(SR); : R = Pr, : R = Me) was investigated, and the crystal structures and thermal properties of the products were examined. The reaction produced the sandwich complexes [RuCp ][X] or dinuclear complexes [RuCp(μ- )(CHCN) ][X] (X = PF, FSA) depending on the reaction conditions. The sandwich complex [RuCp ][FSA] was an ionic liquid. The solids of dinuclear complexes transformed into the thermodynamically stable sandwich complexes upon heating accompanied by acetonitrile loss. This change resulted in a transformation from crystal to ionic liquid for complexes with the FSA anion. UV irradiation of the sandwich complex [RuCp ][PF] in methanol produced the dinuclear complex [RuCp(μ- ) ][PF]. The complex transformed into the sandwich complex upon heating.