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

[Image: see text] To explore the structural transformation of cyclopentadienyl ruthenium (CpRu) complexes in response to external stimuli, the reaction of [RuCp(MeCN)(3)][X] (X = PF(6), (FSO(2))(2)N [= FSA]) and tris(alkylthio)benzenes (1,3,5-C(6)H(3)(SR)(3); L(1): R = Pr, L(2): R = Me) was investigated, and the crystal structures and thermal properties of the products were examined. The reaction produced the sandwich complexes [RuCpL(n)][X] or dinuclear complexes [Ru(2)Cp(2)(μ-L(n))(2)(CH(3)CN)(m)][X](2) (X = PF(6), FSA) depending on the reaction conditions. The sandwich complex [RuCpL(1)][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 [RuCpL(1)][PF(6)] in methanol produced the dinuclear complex [Ru(2)Cp(2)(μ-L(1))(2)L(1)(2)][PF(6)](2). The complex transformed into the sandwich complex upon heating.