84960-61-2Relevant academic research and scientific papers
Diosmium(IV) complexes containing oxide and carboxylate bridges and a weak Os-Os interaction: Structure of (μ-Oxo)bis(μ-acetato)bis[dichloro(triphenylphosphine)osmium(IV)] as its diethyl ether solvate
Armstrong, John E.,Robinson, William R.,Walton, Richard A.
, p. 1301 - 1306 (2008/10/08)
The reactions of trans-OsO2X2(PR′3)2 (X = Cl or Br; PR′3 = PPh3 or PEt2Ph) with refluxing carboxylic acids have produced a new class of diosmium(IV) complexes of the type Os2(μ-O)(μ-O2CR)2X 4(PR′3)2 (R = CH3 or C2H5). The cyclic voltammograms of these complexes show a one-electron reduction with E1/2 values in the range +0.09 to +0.23 V vs. SCE and an irreversible one-electron reduction between -0.79 and -1.01 V. Chemical reduction of Os2(μ-O)(μ-O2CCH3)2Cl 4(PPh3)2 using sodium metal has led to isolation of the Ph4As+ salt of the monoanion. Other characterizations of the diosmium(IV) complexes have included 1H NMR, IR, electronic absorption, and magnetic moment measurements and X-ray photoelectron spectroscopy. The X-ray crystal structure of the diethyl ether solvate of Os2(μ-O)(μ-O2CCH3)2Cl 4(PPh3)2 has been determined. This molecule is the only known example of a diosmium complex containing a single bent bridging oxide ligand. Besides the bridging oxide ligand, two distorted acetate ligands bridge the long Os-Os distance of 3.440 (2) A?. The distorted-octahedral coordination polyhedron about each Os atom is completed by two Cl atoms and a Ph3P ligand. The diethyl ether molecule is disordered in the unit cell. The crystals belong to space group P21/c with a = 13.066 (3) A?, b = 18.124 (3) A?, c = 19.619 (4) A?, β = 107.10 (2)°, V = 4441 A?3, and Z = 4. The structure was solved by the heavy-atom method and refined by full-matrix least-squares procedures with anisotropic temperature factors to R = 0.044 for 4668 observed reflections.
