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

Abstract

This account presents the diverse reactivity of nitridoruthenium(VI) complexes with nucleophilic, electrophilic and oxidizing agents. [Ru VI(N)(L 1)Cl] (1) [H 2L 1 = 2,6-bis(2,2-diphenyl-2-hydroxyethyl)pyridine] reacted with excess phosphines such as PPh 3, PPhMe 2 and dppe to give [Ru III(HL 1)(PPh 3)Cl 2] (2a), [Ru III(L 1)(PPhMe 2) 2Cl] (2b) and [Ru III(L 1)(dppe)Cl] (2c), respectively. In the presence of py or Hpz, 1 was converted to LRu III(L 1)(py) 2Cl] (3a) and [Ru III(L 1)(Hpz) 3]Cl (3b), respectively. A dinuclear μ-nitridoruthenium complex, [Ru IV(L 1)Cl 2(μ-N)Ru VI(L 1)(C 8H 10N)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-Nequiv;Ru moiety with the measured Ru-N distances being 1.661(5) and 1.837(5) Å. Complex 1 reacted with dmf to give [Ru III(HL 1)(dmf)Cl 2] (5) in 17% yield. Excess (Me 3O)BF 4 reacted with 1 to give a dinuclear μ-OH ruthenium complex, [Ru 2(N) 2(L 1) 2(OH)]PF 6 (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-Bu 4N][M VI(N)(L)] [L = L 2 and L 3; M = Os and Ru; H 4L 2 = 1,2-dichloro-4,5-bis(2-hydroxybenzamido)benzene, H 4L 3 = 1,2-bis(2-hydroxybenzamido)benzene], underwent ligand protonation to form [M VI(N)(HL)] complexes, which have been characterized by X-ray crystallography. Oxidation of [n-Bu 4N][Os VI(N)(L 2)] by PhI(OAc) 2 produced [n-Bu 4N][Os VI(N)(L 2O 2)] (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.