Synthesis and reactivities of Ir2Ru heterobimetallic sulfido clusters derived from a hydrogensulfido-bridged diiridium complex

Abstract

The hydrogensulfido-bridged diiridium complex [ClCp*Ir(µ-SH)₂IrCp*Cl] reacted with [RuH₂(PPh₃)₄] to give a mixed-metal trinuclear cluster with an Ir₂Ru(µ₃-S)₂ core [(Cp*Ir)₂(µ₃-S)₂RuCl₂(PPh₃)] 2, which was further converted into the cationic diphosphine derivatives [(Cp*Ir)₂(µ₃-S)₂RuCl(L)]Cl (L = dppe = Ph₂PCH₂CH₂PPh₂ 3 or depe = Et₂PCH₂CH₂PEt₂ 4). The reaction of cluster 3 with Me₂CuLi followed by anion metathesis with KPF₆ afforded the cationic methyl cluster [(Cp*Ir)₂(µ₃-S)₂RuMe(dppe)][PF₆] 5 in good yield, while treatment of 3 with CHCl₂Li led to selective formation of [(Cp*Ir){(η⁴-C₅Me₅CHCl₂)Ir}(µ₃-S)₂RuCl(dppe)] 6, in which one of the Cp* ligands was alkylated by CHCl₂Li to form an η⁴-diene. Clusters 3 and 4 were also transformed into the dihydrido clusters [(Cp*Ir)₂(µ₃-S)₂(µ-H)₂Ru(L)] (L = dppe 7 or depe 8) by the reaction with NaBH₄. On the other hand, cluster 2 was converted into the carbonyl cluster [(Cp*Ir)₂(µ₃-S)₂RuCl(CO)(PPh₃)]Cl 9, the isocyanide clusters [(Cp*Ir)₂(µ₃-S)₂RuCl(CNXy)(PPh₃)]Cl 10 (Xy = 2,6-C₆H₃Me₂) and [(Cp*Ir)₂(µ₃-S)₂Ru(CNXy)₂(PPh₃)][BPh₄]₂ 11 and the co-ordinatively unsaturated thiolato clusters [(Cp*Ir)₂(µ₃-S)₂Ru(SAr)₂] (Ar = 2,4,6-C₆H₂Prⁱ₃ 12 or Xy 13) on treatment with CO, XyNC and LiSAr, respectively. The molecular structures of [(Cp*Ir)₂(µ₃-S)₂RuCl(depe)][BPh₄] 4′, 5·CH₂Cl₂, 6, 7 and 12·2C₆H₆ were established by X-ray diffraction studies.