Ruthenium acetylacetonates

The deposition of platinum, rhodium and ruthenium acetylacetonates on titania takes place by reaction with the surface hydroxy groups to give a supported complex. Thermal decomposition of these supported complexes in vacuum gave highly dispersed titania supported metal catalysts having metal particles about 2 nm in diameter. ... 

Ruthenium dioxide, RuO, displays interesting physical properties such as a low resistivity and high thermodynamic stability [63]. Additionally, the compound exhibits excellent diffusion barrier properties [64] and is used in resistor applications [65]. Precursors for the deposition of RUO2 include ruthenium acetylacetonate, Ru3(CO)i2 (12) and RuCp2 (11) [63, 64]. However, only RuCp produces high quality RUO2 films [63]. 

Ru(CO)5 is prepared by the direct reaction of ruthenium metal with carbon monoxide as shown in eq. (16.2) [9]. Ru(CO)5 is also prepared in high yield by reaction of ruthenium acetylacetonate complex with a mixture gas of CO/H2 (2 1) in heptane [9,10]. 

Osmium forms a 6-coordinate acetylacetonate, Os(acac)3, isomorphous with the ruthenium analogue unlike ruthenium, however, the osmium(IV) complexes Os(acac)2X2 (X = Cl, Br, I) can be made (cis- and frans-isomers exist) from OsXg- and Hacac, as can Os(acac)X [176]. 

Small amounts of hydrocarbons added to the normal tetrahydrofuran or diglyme solvent system result in improved WGSR activity, but larger quantities inhibit the reaction (Table II). When 1-butene or 1-hexene is used, hydroformylation competes with the WGSR (4 ), but the rate of this process is small compared with the rate of H2 production. With pentane, no olefin or aldehyde products could be detected. Calderazzo (29) has reported that Ru(C0) is the principal product when the acetylacetonate of ruthenium is treated with synthesis gas in heptane,... 

In the course of a study on creation of a library of a great number of hetaryl ketones and related derivatives, Szewczyk et al. <2001AGE216> elaborated a ruthenium-catalyzed transformation of heterocycles with activated C-H bond by reaction with olefins and carbon monoxide. Thus, 253 gave 254, albeit in very poor yield. Synthetically, the more straightforward iron-catalyzed transformation was described by Fiirstner et al. <2002JA13856>. These authors reacted 255 with a Grignard reagent in the presence of Fe(acac)3 to afford the 7-alkyl-substituted derivative 256 in reasonable yield (acac = acetylacetonate). 

The ruthenium(111) acetylacetonate-cobalt(II) iodide couple, for example, when dispersed in tetrabutylphosphonium bromide (ex. 1) and treated with 1/1 CO/H2 at 220°C, generates a liquid product containing 76 wt % acetic acid plus 1.1 wt % propionic acid (111 mmol total acid). The liquid yield increase is 66% and the estimated carbon selectivity to acetic plus propionic acids and their esters is 84%. There is normally no metallic residue at this stage, ruthenium and cobalt recovery is essentially quantitative at the end of the run, and the product acids may be recovered in >90% purity by fractional distillation. Methane and water are the major by-products (4). 

In similar but more complicated processes, chelated a-diimines can be formed by reaction of ruthenium(III) and osmium(III) ammine complexes with biacetyl however, reduction of the metal also occurs (Scheme 49).220 A 0-diimine complex is obtained when acetylacetone undergoes reaction with hexaammineplatinum(TV) ions in basic solution (equation 39).220... 

A catalytic amount of ruthenium(III) acetylacetonate (2 mol%) [Ru(acac)3] permits solvent-free tetrahydropyranylation of various types of alcohols and phenols at ambient temperature in moderate to excellent yields.94... 

Figure A.l shows a liquid chromatographic separation of acetylacetonate chelates of beryllium, chromium, ruthenium, and cobalt. The conditions of the separation were ...

Bosnich has recently reported (47) M. O. calculations leading to the assignment of the L configuration to (—)-[Ru(phen)2X2] and states that the same calculations apply to the cis-bis-bidentate complexes of bipyridyl and acetylacetone, and that the phenanthroline and bipyridyl complexes show very similar circular dichroism spectra in the region of the ligand p-band transitions. He comes to a similar conclusion as a result of studies (48) of mixed ruthenium(II) complexes of phenanthroline and bipyridyl. 

Ruthenium trichloride hydrate (5 g.), sodium acetylacetonate (7 g.), and methyl alcohol (140 ml.) are placed in the autoclave in that order. Hydrogen (40 atmospheres) and carbon monoxide (120 atmospheres) (i.e., total initial pressures = 160 atmospheres at room temperature) are then added and the reaction mixture heated at 165° for 4 hours. When cold the pressure is released and the crude orange crystalline dodecacarbonyltriruthenium separated by filtration. The mother liquor is evaporated to dryness and any additional product extracted into hot hexane in a Soxhlet apparatus. The combined products are then recrystallized from hot hexane, f Yields vary slightly from preparation to preparation but are usually in the range 50-55% (2.5 g.). (The checker obtained a yield of 3.0 g., 70%.)... 

The checker reports the following procedure 2.3 g. NaOH as a 40% w/v aqueous solution was added to 5.74 g. acetylacetone (2,4-pentanedione) with stirring. The resultant white, virtually solid, mass was cooled and added to the ruthenium trichloride. 

Pretzer et al. have investigated the hydrogenation potential of different noble metal acetylacetonates in the cobalKatalyzed methanol hydrocarbonylation (c.f. Table VIII). The best results have been obtained with ruthenium, followed by rhodium. In an optimized system of that type, it was possible to achieve 80% molar selectivity to ethanol at a 30% conversion of methanol. Interestingly, the addition of platinum resulted in an increase of acetaldehyde selectivity (20]. 

The first example of a symmetric triangular mixed-valent triruthenium complex 99 has been obtained by thermal treatment of Ru(acac)2(MeCN)2 with substituted 2-thiouracil (equation 66). Although the usual coordination mode of the acetylacetonate is present in the trinuclear compound, the y-carbon atom of one of the coordinated acetylacetonato units of the parent Ru(acac)2(MeCN)2 links to a ruthenium atom forming the trinuclear network. The factors which are primarily involved in the ruthenium-mediated C—S bond cleavage of the stable thiouracyl are not clear. It was suggested that the process starts with the initial coordination of thiouracyl to ruthenium followed by cleavage of the C—S bond and subsequent nucleation. ... 

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