Inorganic Osmium Compounds

Wagner et al. [258] reported a systematic investigation of the isomer shift and quadrupole splitting in various osmium compounds. Of special interest is the comparison with similar or isoelectronic compounds of iridium and ruthenium. 

7 Mossbauer-Active Transition Metals Other than Iron 

It is a matter of historical interest that Mossbauer spectroscopy has its deepest root in the 129.4 keV transition line of lr, for which R.L. Mossbauer established recoilless nuclear resonance absorption for the first time while he was working on his thesis under Prof. Maier-Leibnitz at Heidelberg [267]. But this nuclear transition is, by far, not the easiest one among the four iridium Mossbauer transitions to use for solid-state applications the 129 keV excited state is rather short-lived (fi/2 = 90 ps) and consequently the line width is very broad. The 73 keV transition line of lr with the lowest transition energy and the narrowest natural line width (0.60 mm s ) fulfills best the practical requirements and therefore is, of all four iridium transitions, most often (in about 90% of all reports published on Ir Mossbauer spectroscopy) used in studying electronic stractures, bond properties, and magnetism. 

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If osmium compounds such as osmium tetroxide are used for fixation of the sample chemically, the osmium picked by the micro-organism can make it easier to distinguish saiiples with biological cells from inorganic debris and crystals of approximately the same dimeaisions and shape. 

A number of reviews have been published that survey the general coordination chemistry of ruthenium and osmium. The ehemistry and thermodynamies of ruthenium and its inorganic compounds and aqueous speeies have also been reviewed. ... 

Olefins - [FEEDSTOCKS - COALCHEMICALS] (Vol 10) - [FEEDSTOCKS-PETROCHEMICALS] (VollO) - [HYDROCARBONS - SURVEY] (Vol 13) -m automobile exhaust [EXHAUSTCONTROL, AUTOMOTIVE] (Vol 9) -catalyst for stereospeafic polymerization [TITANIUMCOMPOUNDS - INORGANIC] (Vol 24) -esters from [ESTERIFICATION] (Vol 9) -hydroxylation using H202 [HYDROGEN PEROXIDE] (Vol 13) -luminometer ratings [AVIATION AND OTHER GAS TURBINE FUELS] (Vol 3) -osmium oxidations of [PLATINUM-GROUP METALS, COMPOUNDS] (Vol 19) -polymerization [SULFONIC ACIDS] (Vol 23) -reaction with EDA [DIAMINES AND HIGHER AMINES ALIPHATIC] (Vol 8) -silver complexes of [SILVER COMPOUNDS] (Vol 22)... 

While inorganic complexes of osmium in oxidation states +4 through +8 have been known for many years, the study of high-valent alkyl and aryl complexes of osmium is much more recent. The organometallic complexes include homoleptic see Homoleptic Compound) alkyls and aryls, oxo alkyls and aryls, nitrido/imido alkyls and aryls, and cyclopentadienyl see Cyclopentadienyl) alkyls and aryls. The majority of these are complexes of osmium(VI). 

FIGURE 12.22 As an extension of previous work with inorganic-organic dyads (Figure 12.21), the bimetallic Ru-Os compound shown was designed to promote rapid intramolecular electron transfer (2), after electron injection (1). This process was demonstrated as well as a novel remote injection from the osmium MLCT excited state. 

Preparation of the corresponding cA-16a,17a-diol relies on the known propensity of many inorganic oxidizing agents to produce cA-diols. The sequence for synthesizing that isomer starts with heat-induced elimination of the elements of benzoic acid from estradiol 17-benzoate. The resulting 16-dehydro compound, 31-2, is then treated with osmium tetraoxide (Scheme 3.31). The stereochemistry of that transformation can be rationalized by positing the intermediacy of a complex such as that depicted in 31-3. The overall result is the formation of the c -diol 16a-hydroxy-a-estradiol (31-4). 

Chiu Fan Liu, Nora C. Liu and J. C. Bailar, Jr., The Stereochemistry of Complex Inorganic Compounds. XXVII. Asymmetric Syntheses of Tris-Bipyridine Complexes of Ruthenium-(II) and Osmium(III), Inorg. Chem. 3 1197 (1964). 

A. Neuhaus, A. Veldkamp, and G. Frenking, Inorg. Chem., 33, 5278 (1994). Oxo and Nitrido Complexes of Molybdenum, Tungsten, Rhenium and Osmium. A Theoretical Study. Theoretical Studies of Inorganic Compounds. IV. 

As befits current interest, the largest number of reviews centre on metal carbonyl cluster compounds. General topics covered included electron transfer reactions, ligand and cluster transformations, and the chemistry of metal clusters containing nitrosyl and nitrido ligands.More specific topics reviewed include sulphi do-osmium carbonyl cluster compounds,and homonuclear platinum clusters.The preparations of [Nb(C0)6] [M2(CO)io(m-H)]" (M = Cr or W), Mn2(C0)aX2 and Re C0)sX (X = Cl, Br or I) are described in Volume 23 of Inorganic Syntheses. ... 

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