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, PPhMe2 and dppe to give [RuIII(HL^1)(PPh3)Cl2](2a), [RuIII(L1)(PPhMe2)2Cl](2b) and [RuIII(L^1)(dppe)Cl](2c), respectively. In the presence of py or Hpz, 1 was converted to [RuIII(L^1)(py)2Cl](3a) and [RuIII(L1)(Hpz)3]Cl (3b), respectively. A dinuclear (mu)-nitridoruthenium complex, [RuIV(L^1)Cl2((mu)-N)RuVI(L^1)(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(identical)Ru moiety with the measured Ru-N distances being 1.661(5) and 1.837(5)(angstrom). Complex 1 reacted with dmf to give [RuIII(HL^1)(dmf)Cl2](5) in 17% yield. Excess (Me3O)BF4 reacted with 1 to give a dinuclear (mu)-OH ruthenium complex, [Ru2(N)2(L^1)2(OH)]PF6(6). The measured Ru-O(OH) distance is 1.984 (3)(angstrom) and the average Ru-O-Ru angle was found to be 100.4(2)°. Other nitrido-metal complexes, [n-Bu4N][MVI(N)(L)][L = L^2 and L^3; M = Os and Ru; H4L^2= 1,2-dichloro-4,5-bis(2-hydroxybenzamido)benzene, H4L^3= 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)2 produced [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(identical)N group remained intact.