Ruthenium dioxide hydrated

The addition of OMe to cluster-coordinated GO has been used in the electrospray spectrometry of metal carbonyl complexes.Heterometallic clusters such as Gp Fe(GO)(/x-GO)2Ru2(GO)4(//-H) /x-MeG(GOO)Gl have been obtained upon carbonyl substitution with MeG(Gl)HGOOH on the tetra-heterometallic precursor. An efficient synthetic method for Ru3(GO)i2 starting from ruthenium dioxide hydrate has been reported in the presence of formic or acetic acid, carboxylate complexes are obtained. These favor the reductive carbonylation of nitrobenzene to aniline and A,iV -diphenylurea. 

At one stage in our project we were surprised to learn that some workers had found difficulties in preparing the tetroxide from the dioxide, until we experienced the same trouble. This problem has now been resolved (3). Ruthenium dioxide is available commercially in both anhydrous and hydrated forms, the former being obtained by direct oxidation of ruthenium metal and the latter by a precipitation process. Only the hydrated form is oxidizable under the mild conditions (2,3) that we use and this form must be specified when purchasing the dioxide. It is noteworthy that the dioxide recovered from carbohydrate oxidations is always easily re-oxidized to the tetroxide. The stoichiometry has been determined of both the oxidation of the dioxide by periodate and reduction of the tetroxide which results on oxidation of an alcohol. 

Mild allylic oxidation of the A-2-crotyl-substituted thiadiazolidinone 1,1-dioxide 140 by sodium metaperiodate/ ruthenium trichloride hydrate (RuC13) gave the aldehyde 141. Excess oxidizing agent afforded the carboxylic acid 142 (Equation 26) <1999EJ02275>. 

Ruthenium dioxide [12157-25-6] M 133.1. Freed from nitrates by boiling in distilled water and filtering. A more complete purification is based on fusion in a KOH-KNO3 mix to form the soluble ruthenate and perruthenate salts. The melt is dissolved in water, and filtered, then acetone is added to reduce the ruthenates to the insoluble hydrate oxide which, after making a slurry with paper pulp, is filtered and ignited in air to form the anhydrous oxide [Campbell, Ortner and Anderson AC 33 58 1961]. 

Hydrated ruthenium dioxide will act as a catalyst for the oxidation of primary allylic alcohols (equations 8 and 9) in an oxygen atmosphere (a trace of the antioxidant 2,6-di-r-butyl-4-methylphenol is required to prevent autoxidation of the aldehyde to the acid). The oxidation is not accompanied by any loss in double bond stereochemistry, secondary allylic alcohols are oxidized but at a decreased rate, and saturated alcohols are scarcely oxidized at all. However, a-hydroxy ketones and a-hydroxylactones will oxidize under forcing conditions, so there is clearly likely to some degree of substrate dependence. ... 

Vfiien used in stoichiometric amounts, ruthenium tetroxide is usually prepared by oxidation of hydrated ruthenium dioxide or trichloride with aqueous periodate or hypochlorite and then extracted into carbon tetrachloride. -" However, since ruthenium compounds are expensive it is more common to use only catalytic amounts of Ru02-2H20 or RuQs-HjO in the presence of a cooxidant that continuously regenerates ruthenium tetroxide. 

A solution of 2.4 g (0.012 mol) of ethyl l-acetylpiperidine-2-carboxylate in 40 mL of ethyl acetate is added to a mixture of 0.240 g of hydrated ruthenium dioxide and 120 mL of 10% aqueous solution of sodium periodate (0.056 mol). The mixture is vigorously stirred at room temperature for 14 h. The organic layer is separated, the aqueous layer is extracted with three 40-mL portions of ethyl acetate, and the combined organic solutions are stirred with 2 mL of isopropyl alcohol for 2-3 h to destroy the excess of ruthenium tetroxide. The black ruthenium dioxide that precipitates from the solution is filtered, and the filtrate is washed with 40 mL of water, dried with anhydrous sodium sulfate, and evaporated in vacuo to give 2.42 g (95%) of crude ethyl l-acetyl-6-oxopiperidine-2-carboxylate. 

All operations should be done in th,e hood, because ruthenium tetroxide possesses an unpleasant ozone-lik smell. Commercially available ruthenium dioxide may differ in its properties, especially,in its reaction with sodium periodate, depending on the way it is prepared and on the content of water in its hydrated form [1207],... 

Since 1995, amorphous hydrated ruthenium dioxide, Ru02 H20, has been extensively studied as the electrode materials for the redox capacitor [1-3]. Ru02 H20 composite electrode... 

Fletcher JM, Gardner WE, Greenfie BF, Holdoway MJ, Rand MH (1968) Magnetic and other studies of ruthenium dioxide and its hydrate. J Chem Soc Inorg Phys Theor 653-657... 

The general method for ruthenium tetroxide staining is to stain sections over a fresh 1% solution for about 5-30 min. This is a problem as ruthenium tetroxide solutions are quite unstable, though Trent et al [166] have frozen solutions in sealed glass containers for periods up to six months and report that ruthenium tetroxide can be prepared by oxidation of hydrated ruthenium dioxide using sodium periodate (available from Morton Thiokol, Inc., Alfa Products). The reaction, shown in the following equation [177] ... 

Platinum in a finely divided form is obtained by the in situ reduction of hydrated platinum dioxide (Adams catalyst) finely divided platinum may also be used supported on an inert carrier such as decolourising carbon. Finely divided palladium prepared by reduction of the chloride is usually referred to as palladium black. More active catalysts are obtained however when the palladium is deposited on decolourising carbon, barium or calcium carbonate, or barium sulphate. Finely divided ruthenium and rhodium, usually supported on decolourising carbon or alumina, may with advantage be used in place of platinum or palladium for some hydrogenation reactions. 

Ruthenium Tetrachloride, RuC14, probably exists in solution when the hydrated dioxide, obtained by the action of caustic alkali on the sulphate, is dissolved in hydrochloric acid. It yields a yellow solution from which the tetracliloride cannot be isolated in a pure condition,5 although double salts with the alkali metals have been obtained. These are known as ... 

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