Synthesis of new half-sandwich ruthenium complexes containing 1,2-bis(diisopropylphosphino)ethane (dippe); crystal structures of [Ru(C5Me5)Cl(dippe)] and [Ru(C5Me5)(O2)(dippe)][BPh4]

Abstract

The complex [Ru(C₅H₅)Cl(PPh₃)₂] reacted with 1 equivalent of dippe [dippe = 1,2-bis(diisopropylphosphino)ethane] in refluxing toluene to yield [Ru(C₅H₅)Cl(dippe)]1. The complex [Ru(C₅Me₅)Cl(dippe)]2 was obtained by reaction of [{Ru(C₅Me₅)(µ₃-Cl)}₄] with a stoichiometric amount of dippe in CH₂Cl₂. The crystal structure of 2 has been determined. Both 1 and 2 are non-electrolytes in non-polar solvents. In alcohols, compound 2 has a strong tendency to dissociate chloride. In the presence of air, this compound binds O₂ irreversibly, yielding the dioxygen complex [RuC₅Me₅(O₂)(dippe)]⁺, which is isolable as the [BPh₄]^– salt (3). The crystal structure of this compound has also been determined. Both 1 and 2 reacted with SnCl₂ in CH₂Cl₂ to yield the insertion derivatives [Ru(C₅R₅)(SnCl₃)(dippe)](R = H 4 or Me 5). All compounds were characterized by NMR spectroscopy and microanalysis.