Synthesis and Structure of a Novel Ruthenium Hydrido Bis(dihydrogen) Complex with 1,4,7-Trimethyl-1,4,7-triazacyclononane Ligand: A Useful Precursor for Synthesis of Heterometallic Complexes

The ruthenium hydrido bis(dihydrogen) complex [Cn*RuH(H2)2][PF6] (2-PF6; Cn* = 1,4,7-trimethyl-1,4,7-triazacyclononane) was synthesized by treatment of Cn*RuCl3 with NaBH4. Complex 2-PF6 undergoes a H/D exchange between its hydrido ligands and CD3OD, D2, or THF-d8. Treatment of 2-PF6 with Cp*IrH4 or Cp*OsH5 (Cp* = C5Me5) affords the heterometallic dinuclear polyhydrido complexes [Cn*Ru(μ-H)3IrCp*][PF6] (3-PF6) and [Cn*Ru(μ-H)3OsHCp*][PF6] (4-PF6), respectively. Treatment of 3-PF6 with triphenylphosphine affords the complex [Ru(PPh3)(μ-η3:η1-Cn*CH2)(μ-H)2IrCp*][PF6] (5-PF6), in which the triphenylphosphine is coordinated to the Ru atom as a terminal ligand and the C−H bond of the methyl group in the Cn* ligand is cleaved by the Ir atom. Reaction of 3-PF6 with acetylene gives a bis(μ-vinyl) complex, [Cn*Ru(μ-σ,π-CHCH2)IrH(μ-σ,π-CHCH2)Cp*][PF6] (6-PF6), in which one vinyl ligand is σ-bonded to the Ru atom and the other is σ-bonded to the Ir atom. The molecular structures of 2-PF6, [Cn*Ru(μ-H)3Ir(C5Me4Et)][BPh4] (3′-BPh4), 4-BPh4, 5-BPh4, and 6-PF6 were confirmed by X-ray analyses, and the coordination modes of the hydrido ligands in 2-PF6 were confirmed by density functional theory calculations.