Synthesis and properties of alkylruthenium complexes bearing primary and secondary amine ligands

A series of 18-electron alkylruthenium complexes, RuR[κ2(N,N′)-(S,S)-R′SO2NCHPhCHPhNH2](η6-arene) (Ph = C6H5, R′ = p-CH3C6H4 and CH3), bearing a N-sulfonylated diamine ligand was synthesized from the reaction of RuCl[κ2(N, N′)-(S,S)-R′SO2NCHPhCHPhNH2](η6-arene) with alkylzinc reagents, in which transmetalation proceeded smoothly to give the desired alkyl complexes in good yield and selectivity. Although the isolable amine Ru complexes bearing functionalized alkyl ligands were thermally stable, the simple methyl and ethyl Ru complexes underwent intramolecular deprotonation from NH protons to give the amido Ru complexes with release of the alkanes. The reactivity of the alkyl Ru complexes is highly affected by the structures of the arene ligands.