W. Preetz

Darstellung und eigenschaften von trans(mer)-halogenocarbonylosmaten(III) und -(II)

Abstract The preparation of the trans-dicarbonyls [OsX4(CO)2]− and [OsX4(CO)2]2− (X = Br, I) and of the mer-tricarbonyl [OsI3(CO)3]− as solid and stable salts with various cations is described. The compounds are characterized by spectra in the visible and IR region. The structures are affirmed by some chemical reactions and thermic rearrangements.

Darstellung von cis-tetrahalogenodicarbonylosmaten(II) durch decarbonylierung ungesättigter alkohole

Abstract The reaction of hexahaloosmates(IV) with various unsaturated alcohols produces the mononuclear cis -dicarbonyls [OsX 4 (CO) 2 ] 2− (X = Cl, Br, I) of divalent osmium. The complexes are isolated preferably as tetraethylammonium salts, and are characterized by IR and Raman spectra, while the vibrations are assigned. The dependence of force-constants of the CO bond calculated by the CottonKraihanzel method on halides and the cation as well as the correlation with the bond-angles between the CO-groups are discussed.

Darstellung und eigenschaften von Halogenopyridindicarbonylosmium(II)-komplexen

Abstract On treatment of cis -[OsX 4 (CO) 2 ] 2− (X = Cl, Br, I) with pyridine in ethyleneglycol monoethyl ether at 135°C the complexes cis -[OsX * 2 (py) 2 (CO) 2 (* = ligands in trans -position) are formed. Due to the strong trans -effect of the carbonyl groups the substitution reactions proceed stereospecifically. By oxidative ligand exchange I and Br are replaced stepwise by Br or Cl and by Cl, respectively. The new compounds are characterized by their electronic and vibrational spectra.

Darstellung und eigenschaften von cis-dihalogeno-trans-dipyridin-cis-dicarbonyl-osmium(II)-komplexen

Abstract On tempering in vacuum the partial rearrangement of [OsX★ 2 (py) 2 (CO) 2 ], (X = Cl, Br, I) into the thermodynamically more stable isomers

Darstellung von cis-tetrammindicarbonyl- und fac-triammintricarbonylosmium(II)-halogeniden

Abstract The preparation of cis -[Os(NH 3 ) 4 (CO) 2 ]X 2 (X = Cl, Br, I) by reaction of cis - tetrahalodicarbonylosmate(II) with liquid NH 3 in the supercritical range at 170°C and of fac -[Os(NH 3 ) 3 (CO) 3 ]X 2 by reaction of fac -trihalotricarbonylosmate(II) with liquid NH 3 , at room temperature is described for the first time. The amminecarbonylosmium(II) complexes are extraordinarily stable and are attacked neither by Cl 2 Br 2 nor hot hydrogen halides. The new compounds are characterized by their vibrational and UV-spectra.

Darstellung und eigenschaften von halogenoammindicarbonylosmium(II)-komplexen

Abstract Haloamminedicarbonylosmium(II) complexes are formed by the reaction of cis -[OsX 4 (CO) 2 ] 2− (X = Cl, Br, I) with liquid NH 3 , or of cis -[Os(NH 3 ) 4 (CO) 2 ]X 2 with HX, and can be isolated as intermediates. Due to the different rans -effects the ligand exchange proceeds stereospecifically giving two isomers of cis -[OsCl 2 (NH 3 ) 2 (CO) 2 ], which can be separated by thin layer chromatography. The fac - and mer -forms of [OsX(NH 3 ) 3 (CO) 2 ] + and [OsX 3 (NH 3 )(CO) 2 ] − are detected by electrophoresis. By oxidative ligand exchange of fact -[OsI(NH 3 ) 3 (CO) 2 ] + the corresponding chloro and bromo compounds are formed in good yield.

Stereoisomere trihalogenotricarbonylosmate(II)

Abstract Mononuclear cis -dicarbonyls of divalent osmium react in suitable organic solvents with CO to produce at 20°C mer -[OsX 3 (CO) 3 ] − and at above 100°C fac -[OsX 3 (CO) 3 ] − (X = Cl, Br, I). The bands of the IR and Raman spectra are assigned on the basis of their relative intensities. The force constants, calculated by the Cotton-Kraihanzel method, allow comparison with those of other halocarbonylosmates.

Schwingungs- und UV-Spektren von halogenoammindicarbonylosmium(II)-komplexen

Abstract The structure of the complexes cis-[OsX2(NH3)2(CO)2] and fac-[OsX(NH3)3-(CO)2]X (X = Cl, Br, I) is confirmed by assignment of their IR and Raman spectra. The different trans-effect of the ligands causes characteristic shifts of certain vibrations. The UV spectra of the colourless or light yellow complexes show weak d—d-transitions of the central ion in the region around 300 nm.

Darstellung und spektroskopische charakterisierung von mer-trihalogeno-carbonyl-oxalato-osmaten(III)

Abstract Upon treatment of trans -[OsX 4 (CO) 2 ] − or [OsX 5 (CO)] 2− with oxalate in aqueous solution new complexes of the type mer -[OsX 3 (CO)ox] 2− (X  Cl, Br, I) are formed. The IR and Ra spectra are assigned according to point group C s . In the UV/VIS spectra, recorded at 10 K, charge transfer transitions from ligand levels, splitted by spin-orbit coupling, (π + σ) t 1 u (X) and π t 2 u (X) to t 2 g (Os 3+ ) are observed. Two weak bands with vibrational fine structure in the NIR region are assigned to intraconfigurational transitions within the ground term of osmium(III). The assignment is confirmed by bands of the same frequency observed in the electronic Raman spectrum.

Halogeno-pyridin-carbonyl-osmium-Verbindungen : IV. Darstellung und Eigenschaften von trans-Dihalogeno-mer-tripyridin-monocarbonyl-osmium(II)☆

Abstract On treatment of trans -[OsX 4 (CO) 2 ] − with aqueous pyridine the yellow-orange coloured complexes [Os * 2 (py) 3 CO] ( * = ligands in trans -position) are formed. By oxidative ligand exchange the mixed halo compounds [Os(XY) * (py) 3 CO] (X ≠ Y = Cl, Br, I) may be prepared. The corresponding complexes of osmium-(III) are extremely reducible and therefore cannot be isolated. The new stable compounds are characterized by their electronic and vibrational spectra.