Oxo Complexes of Osmium(IV) Formed via Dioxygen Activation. X-ray Structures of [OsX(dcpe)₂]PF₆ (X = Cl, Br), [OsCl(η²-O₂)(dcpe)₂]BPh₄, and [OsCl(O)(dcpe)₂]BPh₄ (dcpe = 1,2-Bis(dicyclohexylphosphino)ethane)

Abstract

Dioxygen addition to the 16-electron complexes [OsX(P-P)2]+ (3) gives the dioxygen adducts [OsCl(eta 2-O2)(P-P)2]+ (3), which in turn react with HCl gas to give the novel osmium(IV) oxo complexes trans-[OsX(O)(P-P)2]+ (5) (X = Cl, Br; P-P = 1,2-bis(dicyclohexylphosphino)ethane (dcpe), 1,2-bis(diethylphosphino)ethane (depe), 1,2-bis((2R,5R)-2,5-dimethylphospholano)benzene (Me-duphos)). The complexes [OsX(dcpe)2]+ (X = Cl, Br) (3) are studied by X-ray crystallography and are shown to have a "Y-shaped" coordination geometry in the equatorial plane. The X-ray structural analysis of [OsCl(eta 2-O2)(dcpe)2]+ (4a) reveals an exceptionally short O-O bond (1.315(5) A). trans-[OsCl(O)(dcpe)2]+ (5a), the first oxo complex of osmium(IV) investigated crystallographically, exhibits a long Os-O distance of 1.834(3) A. The reactivity of 4 and 5 as oxidants is described. The dioxygen complex 4a transfers one oxygen atom to PPh3 (to give Ph3PO) or oxidizes iodide ions to triiodide ions in the presence of anhydrous HCl. In both reactions, the corresponding oxo species 5a is quantitatively formed as the only metal-containing product. Oxo complexes 5 are surprisingly stable and unreactive toward standard reducing agents such as phosphines.

The Influence of N‐Heterocyclic Carbenes (NHC) on the Reactivity of [Ru(NHC)4H]+ With H2, N2, CO and O2

“…[2][3][4][5] In the majority of cases, structurally characterised examples feature bidentate phosphane ligands with bulky substituents, and this has placed limits on the extent to which these systems can be systematically investigated by variation of the phosphane ligands. One approach to extending the family of [ML 4 H] + species is to replace phosphanes by N-heterocyclic carbenes (NHCs).…”

“…Thus, the Ru (12) and NHC = IMe 4 (13) from reactions performed in pyridine, while the Ru (14) was produced upon reaction of 2 with dioxygen in CD 2 Cl 2 . [5,38] The X-ray crystal structures of these three compounds are provided in the Supporting Information.…”

Fixation of Zinc(II) Ion to Dioxygen in a Highly Deformed Porphyrin: Implications for the Oxygen Carrier Mechanism of Distorted Heme

“…A report showed that dioxygen can be activated via formation of an oxo-osmium(IV) π-complex. 36 1-Zn-O 2 is also a type of π-complex. In 1-Zn-O 2 , the lone electron pair of the terminal O atom, rather than the π electron in the oxo-osmium(IV) complex above, 37 of dioxygen donates an electron pair to a zinc d-orbital to form a σ-coordination bond (Figure 4a-I).…”

Five‐ and Six‐Coordinate Ruthenium(II) Complexes Containing the Bidentate Phosphane (−)‐N,N‐Bis(diphenylphosphanyl)‐(S)‐1‐phenylethylamine [(S)‐peap]: X‐ray Crystal Structure of the First 16‐Electron Ruthenium Complex Bearing a Four‐Membered Ring [RuCl{κ2‐P,P‐(S)‐peap}2][SbF6]·C2H4Cl2

“…The 31 P{ 1 H} NMR spectrum of 1 shows a singlet signal at δ = 78.5, which is clearly downfield with respect to that of the free ligand (δ = 55.3 ppm, br), the deshielding (Δδ = δ complex − δ ligand = +23.2) being intermediate to those found in the analogous trans ‐[RuCl 2 {κ 2 ‐ P , P −Ph 2 PN(R)PPh 2 } 2 ] [R = i Pr (Δδ = +27.1); H (Δδ = +18.0)] 7b. The 31 P{ 1 H} NMR spectrum of 2 shows two triplets (A 2 X 2 spin system) at 72.57 and 87.73 ppm ( 2 J P,P′ = 31.1 Hz) indicating that a single diastereoisomer, Δ( S , S ) or Λ( S , S ), is formed 11. These signals can be assigned to the axial (P trans to P) and equatorial (P trans to Cl) phosphorus nuclei, respectively.…”