Ruthenium crystalline

Ruthenium—Titanium Oxides. The x-ray diffractioa studies of mthenium—titanium oxide coatiags show that the coatiag components are preseat as the metal dioxides, each ia the mtile form as weU as ia soHd solutioa with each other (13). The developmeat of the crystal stmcture begias to occur at a bake temperature of about 400°C. By foUowiag the diffractioa line for the mtile stmcture, an iacrease ia crystallinity can be seen as temperatures are iacreased to the 600—700°C range. Above these temperatures, the peak begias to separate iato two separate peaks, iadicative of phase separatioa iato iadividual mtile oxides, oae rich ia mthenium and one rich ia titanium. 

The crude, but essentially pure, dibenzo-18-crown-6 obtained from the Organic Syntheses preparation described above (Eq. 3.11) may be hydrogenated in M-butanol solution over 5% ruthenium on alumina, in a stainless steel autoclave at 1,000 p.s.i.. Di-cyclohexano-18-crown-6 is obtained from this treatment in 58—69% yield as a mixture of crystalline diastereomers having a melting range of 38-54°. 

In contrast to ruthenium, osmium exists in alkaline solution as 0s04(0H)2, believed to be cis and isolable as crystalline salts ... 

The radiochemistry of ruthenocene has been studied by Baumgartner and Reichold (9) and by Harbottle and Zahn (29). It is found that neutron irradiation of crystalline RuCp2 yields about 10% of the radioactive ruthenium as RuCp2- More specifically, an isotopic difference in the radiochemical yield is found Ru, 9.6 0.1% Ru, 10.7 0.2% and Ru, 9.9 0.2% (29). In liquid solution the isotopic effect is much more pronounced, although the yields are lower. This was suggested by Harbottle as a general principle the greatest isotope effects are associated with the lowest yields. While this principle has not yet been substantiated, it seems reasonable since any thermal reactions which may increase the yields would not likely show any isotope effect. 

Recently, rhodium and ruthenium-based carbon-supported sulfide electrocatalysts were synthesized by different established methods and evaluated as ODP cathodic catalysts in a chlorine-saturated hydrochloric acid environment with respect to both economic and industrial considerations [46]. In particular, patented E-TEK methods as well as a non-aqueous method were used to produce binary RhjcSy and Ru Sy in addition, some of the more popular Mo, Co, Rh, and Redoped RuxSy catalysts for acid electrolyte fuel cell ORR applications were also prepared. The roles of both crystallinity and morphology of the electrocatalysts were investigated. Their activity for ORR was compared to state-of-the-art Pt/C and Rh/C systems. The Rh Sy/C, CojcRuyS /C, and Ru Sy/C materials synthesized by the E-TEK methods exhibited appreciable stability and activity for ORR under these conditions. The Ru-based materials showed good depolarizing behavior. Considering that ruthenium is about seven times less expensive than rhodium, these Ru-based electrocatalysts may prove to be a viable low-cost alternative to Rh Sy systems for the ODC HCl electrolysis industry. 

For catalyst combinations containing initial I/Ru ratios 5, the product solutions also show strong new bands at 1999 and 2036 cm characteristic (6) of ruthenium pentacarbonyl. Where acetic acid homologation is run at [RuJ > 0.2 M, then another ruthenium iodocarbonyl, Ru(C0)3I2, may be isolated from the product mix as a yellow crystalline solid. A typical spectrum of this material is illustrated in Figure 3b. 

Some precipitation methods have been applied to the separation of technetium from molybdenum when the former occurs as a radio-active daughter-product of the latter. The separation of technetium is performed by co-precipitation with tetraphenylarsonium perrhenate from an alkaline molybdate solution . In this way, also ruthenium remains in solution. Molybdate may be precipitated away from pertechnetate using 8-hydroxyquinoline " or a-benzoinoxim Pb or Ag" ions can also be used . Kuzina and Spitsyn have developed a method for concentrating technetium from ammoniacal molybdate solutions by co-precipitat-ing pertechnetate with the slightly soluble crystalline MgNH PO. ... 

When heated in air at 500 to 700°C, ruthenium converts to its dioxide, Ru02, a black crystalline solid of rutile structure. A trioxide of ruthenium, RuOs, also is known formed when the metal is heated above 1,000°C. Above 1,100°C the metal loses weight because trioxide partially volatilizes. 

Ruthenium reacts with cyclopentadiene in ether to form a sandwich complex, a yellow crystalline compound, bis(cyclopentadiene) ruthenium(0), also known as ruthenocene. 

Method E To a suspension of 0.67 mM of ruthenium(IV) dioxide dihydrate in 0.8 mL of trifluoroacetic acid, 0.4 mL of trifluoroacetic anhydride, and 4 mL of CH2C12 at 0 C is added, with stirring and under argon, a solution of 0.33 mM of prestegane B in 4mL of CH2C12 and, immediately, 0.2 mL of boron trifluoride-diethyl ether complex. After 3 h. the suspended solid is removed by filtration. Evaporation and flash chromatography affords the pure crystalline product yield 84% mp 228-230°C. 

A solution of 18 g (68 mmol) of commercial ruthenium trichloride hydrate (Johnson Matthey, 40 3% ruthenium) in a mixture of isoprene (680 mL) and 2-methoxyethanol (280 mL) is heated at reflux for 10 days under inert gas (nitrogen or argon). The purple crystalline product is collected in a medium-porosity sintered-glass funnel, washed with diethyl ether, and dried in vacuo yield 19.9 g (95%). 

These hydroxo-salts are all sulphur-yellow crystalline substances. The acid residues are hydrolysable and hence outside the co-ordination complex, and the aqueous solutions, unlike the hydroxo-salts of chromium-and cobalt-ammines, are neutral to litmus, a fact which Werner suggests is due to the smaller tendency of the hydroxo-radicle attached to ruthenium to combine with hydrogen ions. This tendency is much less than in the case of the ammines of cobalt and chromium, but that it still exists is indicated by the increased solubility of these hydroxo-compounds in water acidified with mineral acids, and from such solutions aquo-nitroso-tetrammino-ruthenium salts are obtained thus ... 

It is clear from the preceding section that the field of tethered arene-metal complexes is dominated by ruthenium and by arene-phosphines as ligands. In part, this situation has arisen because of the current surge of interest in the catalytic properties of ruthenium complexes in organic synthesis.85,86 Moreover, the tethered arene complexes are usually air-stable, crystalline solids with a well-defined, half-sandwich molecular geometry that, in principle, can lock the configuration at the metal centre. These compounds should, therefore, be ideal both for the study of the stereospecificity of reactions at the metal centre and for stereospecific catalysis. 

Treatment of [ C5(CH3)5 RuCl]4 with 3,5-dimethylpyrazolatopotassium, 3,5-diphenylpyrazo-lato(tetrahydrofuran)potassium, or 3,5-di-/m-butylpyrazolatopotassium in tetrahydrofuran afforded (r 5-3,5-dimethylpyrazolato)(r 5-pentamethylcyclopentadienyl)rathenium(II) (71 %), (r 5-3,5-di-tert-butylpyrazolato)(r 5-pentamethylcyclopentadienyl)ruthenium(II) (72%), or (r 5-3,5-diphenylpyrazolato)(r 5-pentamethylcyclopentadienyl)ruthenium(II) (71%), as dark green, pale yellow, or dark brown crystalline solids, respectively. 

Ferulic acid, a phenolic acid that can be found in rapeseed cake, has been used in the synthesis of monomers for ADMET homo- and copolymerization with fatty acid-based a,co-dienes [139]. Homopolymerizations were performed in the presence of several ruthenium-based olefin metathesis catalysts (1 mol% and 80°C), although only C5, the Zhan catalyst, and catalyst M5i of the company Umicore were able to produce oligomers with Tgs around 7°C. The comonomers were prepared by epoxidation of methyl oleate and erucate followed by simultaneous ring opening and transesterification with allyl alcohol. Best results for the copolymerizations were obtained with the erucic acid-derived monomer, reaching a crystalline polymer (Tm — 24.9°C) with molecular weight over 13 kDa. 

The Ru02 particles can not be reduced at room temperature, but reduce readily at 773 K. The ruthenium particles produced after this reduction procedure are estimated to be 16 nm in diameter from x-ray diffraction line width analysis. The reduction results in further loss of crystallinity, reflected by a drop in surface area and microporosity (Table 2). In addition, the position of the asymmetric T-O stretching vibration is at 1071 cm" 1, indicating a very silicon-rich material. 

According to the standard electrochemical potentials (Table 1), with Cu/Cu2+ and Ru/Ru3+ couples, the amount of ruthenium deposited on metallic copper will be small, whereas the redox reaction carried out in presence of platinum or gold salts will occur to a large extent. On the other hand, for electrodes of first type (metal immersed in a solution of a salt of that metal), the standard electrochemical potentials as defined by thermodynamics are calculated with regard to a poly-crystalline metallic phase of infinite size. However, in the case of small metallic particles, characterized by metallic atoms of different coordination numbers, the notion of a local potential can be introduced. That no-... 

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