Of Ru

Photoexcited fluorescence from spread monolayers may be studied [158,159] if the substance has both a strong absorption band and a high emission yield as in the case for chlorophyll [159]. Gaines and co-workers [160] have reported on the emission from monolayers of Ru(bipyridine)3, one of the pyridine ligands having attached C g aliphatic chains. Ruorescence depolarization provides information about the restriction of rotational diffusion of molecules in a monolayer [161], Combining pressure-area... 

The relative intensity of a certain LEED diffraction spot is 0.25 at 300 K and 0.050 at 570 K using 390-eV electrons. Calculate the Debye temperature of the crystalline surface (in this case of Ru metal). 

In the case of Ru(2,2 -bipyridine)3 adsorbed on porous Vycor glass, it was inferred that structural perturbation occurs in the excited state, R, but not in the ground state [209]. 

The most abundant literature is that bearing on solar eneigy conversion, mainly centered on the use of Ru(2,2 -bipyridine)3 and its analogues. The excited state of the parent compound was found some years ago to be a powerful reducing agent [212], allowing the following spontaneous reactions to be written ... 

The UV-visible absorption spectrum of Ru(2,2 -bipyridine)3 maximum at about 450 nm, from which the energy in volts for process XI-39 may be estimated. The standard reduction potential for the R" /R couple is about 1.26 V at 25°C. Estimate from this information (and standard reduction potentials) the potential in volts for processes XI-40 and XI-41. Repeat the calculation for alkaline solutions. 

A few illustrative examples are the following. Photohydrogenation of acetylene and ethylene occurs on irradiation of Ti02 exposed to the gases, but only if TiOH surface groups are present as a source of hydrogen [319]. The pho-toinduced conversion of CO2 to CH4 in the presence of Ru and Os colloids has been reported [320]. Platinized Ti02 powder shows, in the presence of water, photochemical oxidation of hydrocarbons [321,322]. Some of the postulated reactions are ... 

Stampfl C and Scheffler M 1997 Anomalous behavior of Ru for catalytic oxidation a theoretical study of the catalytic reaction CO+1/2 O2 to CO2 Phys. Rev. Lett. 78 1500... 

The methodology used in the preparation of RU 486 (84) and other ll -steroids is shown. Conjugate addition of a cuprate reagent to the a,P-unsaturated epoxide (85) provides the liP-substituted steroid (86) stereospecificaHy (131). Subsequent steps lead to the synthesis of RU 486 (84). 

Mifepristone. After oral adininistration, peak plasma levels of mifepristone (84) (RU 486) are reached in 1 h and over 95% was bound to plasma proteins (351,352). The plasma half-life of RU 486 is approximately 24 h (352,353). In humans, monodemethylated (98), didemethylated (99) and alcohoHc nondemethylated (100) metaboHtes of RU 486 have been identified (351). These metaboHtes show some progestin-binding affinity, approximately five to ten times lower than that of RU 486 itself. RU 486 and its metaboHtes can be measured by radioimmunoassay and hplc (353,354). 

The method of extraction of Ru(III) from thiocyanate solutions by water soluble extractants in the presence of ammonium sulfate as salting out agent followed by photometric determination of it in extract has been elaborated. 

Method of Rh(III) - Ru(III) separation and isolation them from rai e and nonferrous metals based on formation of different charged complexes with varied stability has been proposed. Possibility of sepai ation of Ru(III), Rh(III), Pd(II), Pt(II) by water-soluble extractants from concentrated thiocyanate solutions has been displayed. Accelerated procedures of extraction-photometric determination of Rh(III), Ru(III) in solutions and waste products, which ai e chai acterized by high selectivity, availability, usage of non-toxic extractants have been worked out. 

The tetrahydropyranyl ether, prepared from a phenol and dihydropyran (HCl/EtOAc, 25°, 24 h) is cleaved by aqueous oxalic acid (MeOH, 50-90°, 1-2 h). Tonsil, Mexican Bentonite earth, HSZ Zeolite, and H3[PW,204o] have also been used for the tetrahydropyranylation of phenols. The use of [Ru(ACN)3(triphos)](OTf)2 in acetone selectively removes the THP group from a phenol in the presence of an alkyl THP group. Ketals of acetophenones are also cleaved. ... 

Ru and Os, along with Ir, are regarded as the minor platinum metals, being obtained largely as byproducts in the production of Pt, Pd and Rh, and their annual world production is only of the order of tonnes. (Weights of Ru and Os, as of most precious metals, are generally quoted in troy ounces 1 troy ounce = 1.097 avoirdupois ounce = 31.103 g.)... 

Ruthenium and osmium have no oxides comparable to those of iron and, indeed, the lowest oxidation state in which they form oxides is -t-4. RUO2 is a blue to black solid, obtained by direct action of the elements at 1000°C, and has the rutile (p. 961) structure. The intense colour has been suggested as arising from the presence of small amounts of Ru in another oxidation state, possibly - -3. 0s02 is a yellowish-brown solid, usually prepared by heating the metal at 650°C in NO. It, too, has the rutile structure. 

The most interesting oxides of Ru and Os, however, are the volatile, yellow tetroxides, RUO4 (mp 25°C, bp 130°C< 3>) and OSO4 (mp 40°C, bp 130°C). They are tetrahedral molecules and the latter is perhaps the best-known compound of osmium. It is produced by aerial oxidation of the heated metal or by oxidizing other compounds of osmium with... 

By heating the metal with appropriate oxides or carbonates of alkali or alkaline earth metals, a number of mixed oxides of Ru and Os have been made. They include NasOs Og, LifiOs Og and the ruthenites , M Ru 03, in all of which the metal is situated in octahedral sites of an oxide lattice. Ru (octahedral) has now also been established by Ru Mdssbauer spectroscopy as a common stable oxidation state in mixed oxides such as Na3Ru 04, Na4Ru2 07, and the ordered perovskite-type phases M Ln Ru Og. 

Figure 2S J Teiramenc pentafluondes of Ru and Os, Their structures are similar to, but more disloned than, those of the pentafloorides of F4b and Ta (see Fig. 22 4)...

Fluorides and 0x0 compounds of Ru and Os have already been mentioned, and salts such as (R4N)[Ru04l, (R = n-propyl, n-butyl) are useful reagents to oxidize a variety of organic materials without attacking double or allylic bonds,... 

This is also the case in the decamethylmetal-locenes of Ru and Os but not in the iron analogue which has a staggered conformation, presumably due to steric crowding around the smaller metal. 

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