Osmium , dihydrate

In the currently preferred variant of this reaction, one introduces a mixture of dipotassium osmate dihydrate (K20s04 2Hd)) as a nonvolatile source of osmium (rather than osmium tetroxide), along with potassium hexaeyannferrate(III) (Ki[Fe(CN)6J) as cooxidizing... 

Alternate sources of osmium can be used and should be considered, as they offer advantages in ease of handling. Both osmium(III) chloride hydrate [OsCl xHjO] [30] and potassium osmate(VI) dihydrate [K2OsO2(0H)4] [31] have been used as replacements for osmium tetroxide, and the latter reagent is specified in the preceding standard set of conditions for catalytic AD. 

OSQ3N4C20H16 2H2O, Osmium(III), bis-(2,2 -bipyridine-N, N )didiloro-, cis-, chloride, dihydrate, 24 293... 

OSF9N5O10S3C28H31 2H2O, Osmium(III), aqua(2,2 -bipyridine-iV,N )(2,2 6, 2"-terpyridine-N,N, N")-, tris(trifluoro-methanesulfonate), dihydrate, 24 304 0sF9N60,S3C3H,8, Osmium(III), hexaam-mine-, tris(trifluoromethanesulfonate), 24 273... 

CrN2S2C 4H g2H20, Chromium(II), tetra-aquabis(l,2-benzisothiazol-3(27/)-one 1,1-dioxidato)-, dihydrate, 27 309 0,oHOs3C H3, Osmium, decacarbonyl-hydridomethyltri-, 27 206 0,gH20s3C H2, Osmium, decacarbonyl-di-p-hydrido-p-methylene-tn o/igu/o-tri-, 27 206... 

These complexes are prepared by aquation of the corresponding triflato complexes that are prepared in Section C. This is readily accomplished by allowing the hygroscopic solids obtained from the triflic acid/diethyl ether solutions (before vacuum oven drying) to fully aquate in air for 1 day. Storage in a vacuum desiccator over P40,o permits the isolation of the trihydrate and dihydrate complexes for ruthenium and osmium, respectively. The yields are the same as those found for the production of the triflato complexes in Section C. 

The aqua osmium(II) complex is prepared by reduction of the aqua osmium(III) complex (prepared as in Section E). Aqua(2,2 -bipyridine-A, A )(2,2 6, 2"-ter-pyridine-yV,A, iV")osmium(III) trifluoromethanesulfonate dihydrate (0.5(X) g, 4.063 mmol) is dissolved in 0.33 M CF3SO3H (30 mL), and the solution is filtered. Two pieces of freshly prepared zinc amalgam are added. The solution is stirred for 5 hr. The zinc is removed, and the solution is cooled in an ice bath. The resulting black crystals are filtered off, washed with ice cold water (2x2 mL), and dried under vacuum. Yield 0.224 g (53%). A second crop may be obtained by addition of fresh zinc amalgam to the filtrate. 

Accordingly, the dihydrate should be a tetrabasic acid if the acidity were due to the hydrogen of the hydroxyl, but this is contrary to experimental facts. Similarly, osmium and ruthenium oxides might be expected to show a greater tendency to form acids than sulfur trioxide since they contain more oxygen atoms with double linking to combine with the water. It is evident, therefore, that a knowledge of the co-ordination number as well as of the atomic valence is necessary in order to determine the basicity of an acid. 

N20ioOs3C,4Hg, Osmium, bis(acetonitriie)-decacarbonyltri-, 26 292 N20,oS2VC,4H, -2H20, Vanadium(II), tetraaquabis( 1,2-benzisothiazol-3(2if > one 1,1-dioxidatoK dihydrate, 27 307 N20i2P4PtRh4Cg4Hjg, Rhodate(2—), dode-cacarbonylplatinumtetra-, bis[/i-nitrido-... 

The avoidance of a-ketol by-products is an important feature of a new catalytic osmylation procedure for the preparation of cis-1,2-diols. Reaction involves treatment of the olefin with N-methylmorpholine iV-oxide dihydrate in aqueous acetone, and osmium tetroxide in t-butyl alcohol at 25 °C, overnight. Reduction (NaHS03), adsorption on to magnesium silicate, filtration, neutralization, and ethyl acetate extraction afforded the diols in moderate to excellent yield. An example is the synthesis of (397 55 %) from (396). 

F24N12OS2P4C 58H44 2H2O, Osmium(II), tetra-kis(2,2 -bipyridine)-m-[2,3-bis(2-pyridyl)-quinoxaline]-, cis-, di-, hexafluoro-phosphate(l-), dihydrate, 33 33 F24N12OS2P4C62H46 3H2O, Osmium(II), tetra-kis(2,2 -bipyridine)-m-[2,3-bis(2-pyridyl)-benzoquinoxaline]-, cis-, di-, hexafluoro-phosphate(l-), trihydrate, 33 34 F48B2C0N6C76H42, Cobalt(II), hexakis(acetoni-trile)-, bis[tetra-3,5-bis(trifluoromethyl)-phenylborate], 33 87... 

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