CLOS Research Articles

English

English

Substituent-Induced Reactivity in Quinonoid-Bridged Dinuclear Complexes: Comparison between the Ruthenium and Osmium Systems

The ligand 2,5-bis[2-(methylthio)anilino]-1,4-benzoquinone (L) was used in its doubly deprotonated form to synthesize the complex [{Cl(η6-Cym)Os}2(μ-η2:η2-L-2H)] (1; Cym = p-cymene = 1-isopropyl-4-methylbenzene). Spectroscopic characterization and elemental analysis confirms the presence of the chloride ligands in 1, which indirectly shows that the bridging ligand L-2H acts in a bis-bidentate fashion in 1, with the thioether substituents on the bridge remaining uncoordinated. Abstraction of the chloride ligands in 1 by AgBF4 in CH3CN leads not only to the release of those chloride ligands but also to a simultaneous substituent-induced release of Cym with the bridging ligand changing its coordination mode to bis-tridentate. In the resulting complex [{(CH3CN)3Os}2(μ-η3:η3-L-2H)]2+ (22+), the thioether groups of L-2H are now coordinated to the osmium centers with the bridging ligand coordinating to the metal center in a bis-meridional form. The coordination mode of L-2H in 22+ was confirmed by single-crystal...

Bis[bis(triphenylphosphoranylidene)ammonium] Pentachlorofluoroosmate(IV) Hydrate, [(C6H5)3P= N= P(C6H5)3]2[OsFCl5].H2O

The structure of the title compound, (C36H30NP2)2[OsCl5F].H2O, has been determined by single-crystal X-ray diffraction at 208 K. The octahedral [OsCl5F]2− complex anions are completely ordered in an A2B-type lattice. The monoclinic unit cell contains four formula units, each with a solvent water molecule linked to the F ligand by a hydrogen bond [O⋯F 2.737 (8) Å]. The Os—F bond [1.960 (4) Å] is weakened by a trans influence and, correspondingly, the Os—Cl1 bond [2.307 (2) Å] trans to Os—F is strengthened compared with the average Os—Cl bond length along the Cl—Os—Cl axes of 2.339 Å.

Tax systems in the reforming socialist economies of Europe

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Schwingungsspektren und Normalkoordinatenanalyse der Chloro-Bromo-Osmate(IV), [OsCl„Br6-n]2-, n = 0-6 / Vibrational Spectra and Normal Coordinate Analysis of Chloro-Bromo-Osmates(IV), [OsCl„Br6-n]2-, n = 0-6

The IR- and Raman spectra of the ten chloro-bromo-osmates(IV) [OsCl„Br6-n]2-, n = 0-6, including the geometrical isomers for n = 2, 3, 4 have been recorded at low temperature (80 K). The vibrational spectra of these complexes are completely assigned according to point groups Oh, D4h, C4v, C3v and C2v, supported by normal coordinate analyses based on a general valence force field. Due to the stronger trans-influence of Br as compared to Cl, in all asymmetric Cl—Os—Br axes the Os—Br bonds are strengthened and the Os—Cl bonds are weakened, indicated by valence force constants for Os— Br approximately 6% higher, for Os—Cl 6% lower, as compared with the values calculated for symmetrical Br—Os—Br and Cl-Os-Cl axes, respectively. The significantly stronger interaction between opposite bonds is revealed by the stretching interaction constants fdd, which are about three times larger than fdd for bonds at right angles.

TICLOS: an implementation of CLOS for the explorer family

TICLOS: an implementation of CLOS for the explorer family

Preparation and crystal structure of trichloro(thionitrosyl)bis(triphenylphosphine)osmium, [Os(NS)Cl3(PPh3)2

The compound (NSCl)3 reacts with [MCl2(PPh3)3](M = Os or Ru) in tetrahydrofuran to give the thionitrosyl complexes [M(NS)Cl3(PPh3)2][M = Os (1) or Ru (2)]. Nitrosyl chloride or bromide converts (1) to the corresponding nitrosyl complex. Crystals of (1) are monoclinic, space group I2/a, with a= 1 615.9(6), b= 943.7(5), c= 2 250.6(10) pm, β= 103.02(3)°, and Z= 4. The structure was refined to R= 0.042 for 2 076 diffractometer data. The osmium is octahedrally co-ordinated with the phosphines cis to the NS group; a crystallographic two-fold axis along the Cl–Os–N–S bonds imposes linearity at nitrogen, with Os–N 177.9(9), N–S 150.3(10), Os–P 245.9(2), Os–Cl(cis) 238.7(3), and Os–Cl(trans) 239.9(3) pm. Complex (2) is apparently isostructural, with a= 1 613.5(15), b= 941.8(4), c= 2 249.3(15) pm, and β= 102.94(3)°.

Kinetische untersuchungen zum isotopen-und ligandenaustausch an chloro-jodo-osmaten(IV)

The isotopic and ligand exchange of stereospecifically 36Cl-labelled mixed-ligand complexes of the type [OsCl n I 6− n ] 2− is described. The kinetical data are significantly influenced by the different trans-effect of the two halides. The rates of isotopic exchange for Cl-ligands trans-positioned to I are 180–800 times greater and the activation energies about 4–6 kcal/mol lower than for a ClOsCl-axis. The substitution of the Cl-ligands against I − is strongly favored in comparison to the isotopic exchange.