A straightforward and generalizable synthetic methodology for the synthesis of ruthenium(ii) complexes with thioether ligands from either Ru(iii) or Ru(0) precursors

Abstract

The reaction of Ru₃(CO)₁₂ in chloroform with thioether ligands after 25 min of irradiation leads to the formation of mononuclear ruthenium(II) complexes of the general formula fac-[Ru(CO)₃Cl₂(S)] (S = thioether) if monodentate ligands are introduced. In the case of chelating bidentate thioethers a complex of the formula all-cis-[Ru(CO)₂Cl₂(S∩S)] is produced. If irradiation time is prolonged to 2.5 h mononuclear complexes of the composition trans-[RuCl₂(S)₄] or trans-[RuCl₂(S∩S)₂] are observed. The use of tetrahydrothiophene (THT) in the latter case produces a dinuclear ruthenium(II) complex of the formula [Ru₂(CO)₂Cl₄(THT)₂(μ-THT)₂] which is the first structurally characterized neutral ruthenium complex with a bridging thioether ligand. Regardless of the used ligand complexes trans-[RuCl₂(S)₄] or trans-[RuCl₂(S∩S)₂] are formed from the reaction of RuCl₃·3H₂O with the corresponding thioether in the presence of NEt₃ and formaldehyde in excellent yields. Six new ruthenium complexes are characterized by X-ray diffraction.