Synthesis and Structures of Dinuclear 3,5-Bis(trifluoromethyl)pyrazolate Complexes of Ruthenium

Reaction of 3,5-(CF3)2PzLi with [Cp*RuCl2]n (2:1) in diethyl ether at −78 °C gives [(Cp*RuLi)2(μ4-O)(μ2-Cl)(μ-3,5-(CF3)2Pz)3] (1) in 75% yield [3,5-(CF3)2Pz = 3,5-bis(trifluoromethyl)pyrazolate]. With a 1:1 ratio of [Cp*RuCl2]n to 3,5-(CF3)2PzLi, dark-green crystalline [Cp*Ru(μ-Cl)]2(μ-3,5-(CF3)2Pz) (2) is produced in ca. 50% yield. The reaction of 3,5-(CF3)2PzLi with [RuCl2(1,4-Me,iPrC6H4)]2 in diethyl ether at −78 °C gives the chloride-bridged dimer [RuCl(η6-1,4-Me,iPrC6H4)(μ-3,5-(CF3)2Pz)]2 (3) in 65% yield. The reaction of Cp*Ru(OSO2CF3)2 with 3,5-(CF3)2PzLi (2:1) in diethyl ether at −78 °C produced the unusual dinuclear RuIII−RuIII complex [Cp*Ru(μ-O)(μ-η5,η1-C5Me4CH2)Ru(η1-3,5-(CF3)2Pz)]·0.25Et2O (4) in 75% yield. Complexes 1–4 have been characterized spectroscopically and by single-crystal X-ray diffraction studies.