Nitrido-ruthenium(vi) and -osmium(vi) complexes of multianionic chelating (N, O) ligands. Reactions with nucleophiles, electrophiles and oxidizing agents

This account presents the diverse reactivity of nitridoruthenium(vi) complexes with nucleophilic, electrophilic and oxidizing agents. [RuVI(N)(L1)Cl] (1)[H2L1= 2,6-bis(2,2-diphenyl-2-hydroxyethyl)pyridine] reacted with excess phosphines such as PPh3, PPhMe2and dppe to give [RuIII(HL1)(PPh3)Cl2](2a), [RuIII(L1)(PPhMe2)2Cl](2b) and [RuIII(L1)(dppe)Cl](2c), respectively. In the presence of py or Hpz, 1 was converted to [RuIII(L1)(py)2Cl](3a) and [RuIII(L1)(Hpz)3]Cl (3b), respectively. A dinuclear μ-nitridoruthenium complex, [RuIV(L1)Cl2(μ-N)RuVI(L1)(C8H10N)Cl](4), was obtained by treating 1 with 2,6-dimethylaniline. Based on X-ray crystallographic study, the compound is characterized by an unsymmetrical Ru–N≡Ru moiety with the measured Ru–N distances being 1.661(5) and 1.837(5)Å. Complex 1 reacted with dmf to give [RuIII(HL1)(dmf)Cl2](5) in 17% yield. Excess (Me3O)BF4reacted with 1 to give a dinuclear μ-OH ruthenium complex, [Ru2(N)2(L1)2(OH)]PF6(6). The measured Ru–O(OH)distance is 1.984(3)Å and the average Ru–O–Ru angle was found to be 100.4(2)°. Other nitrido-metal complexes, [n-Bu4N][MVI(N)(L)][L = L2and L3; M = Os and Ru; H4L2= 1,2-dichloro-4,5-bis(2-hydroxybenzamido)benzene, H4L3= 1,2-bis(2-hydroxybenzamido)benzene], underwent ligand protonation to form [MVI(N)(HL)] complexes, which have been characterized by X-ray crystallography. Oxidation of [n-Bu4N][OsVI(N)(L2)] by PhI(OAc)2produced [n-Bu4N][OsVI(N)(L2O2)](8) in 10% yield. X-ray structure analysis of 8 showed that the coordinated phenoxy moiety was converted to a benzoquinone moiety while the Os≡N group remained intact.