Ruthenium phosphine modified

The use of catalysts based on polymers with inverse temperature solubility, often copolymers of TV-isopropy-lacrylamide, to allow recovery by raising the temperature to precipitate the polymer for filtration,9 was mentioned in Chap. 5. The opposite, if the catalyst is soluble hot, but not cold, has also been used in ruthenium-catalyzed additions to the triple bonds of acetylenes (7.1).10 The long aliphatic tail of the phosphine ligand caused the catalyst to be insoluble at room temperature so that it could be recovered by filtration. There was no loss in yield or selectivity after seven cycles of use. A phosphine-modified poly(A-iso-propylacrylamide) in 90% aqueous ethanol/heptane has been used in the hydrogenation of 1-olefins.11 The mixture is biphasic at 22°C, but one phase at 70°C, at which the reaction takes place. This is still not ideal, because it takes energy to heat and cool, and it still uses flammable solvents. 

The fact that water-soluble sulfonated phosphines may combine the properties of a ligand and a surfactant in the same molecule was first mentioned in 1978 by Wilkinson etal. [11] in their study of the hydroformylation of 1-hexene using rhodium and ruthenium catalysts modified with TPPMS (triphenylphosphine mono-... 

Because propylene is frequently quite expensive and in short supply, BASF has applied for a patent on a new route to n-butyraldehyde and/or n-butanol starting from butadiene. They found that a homogeneous palladium acetonylacetonate catalyst with phosphine ligands would allow butadiene to react with n-butanol to produce l-n-butoxy-2-butene (nBB). nBB will then react with more n-butanol to produce the acetal, using a homogeneous phosphine modified ruthenium catalyst. The acetal can be hydrolyzed to n-butyraldehyde, or hydrogenated and hydrolyzed to n-butanol using the same Ru catalyst. 

Both academia and industries made important contributions to the new field in the early sixties with the appearance of the first phosphine modified and other hydrogenation catalysts. An early example of a phosphine-free ruthenium catalyst was published by Halpem [6]. In 1963 Cramer (Du Pont) reported a triphenylphosphine-modified platinum-tin catalyst for the hydrogenation of alkenes [7], In the same year Breslow (Hercules) included a few phosphine complexes of late transition metals in a hydrogenation study employing metal salts reduced by aluminum alkyls, but interestingly the systems containing phosphine were less active [8] ... 

Kalck and coworkers [114] investigated dinuclear ruthenium complexes modified with NEtj or PPhj. Replacement of the latter by P(OPh)3 diminished the rate of hydrogenation as well as the isomerization disposition. A similar effect was found by using an excess of phosphine. 

For the synthesis of carbohydrate-substituted block copolymers, it might be expected that the addition of acid to the polymerization reactions would result in a rate increase. Indeed, the ROMP of saccharide-modified monomers, when conducted in the presence of para-toluene sulfonic acid under emulsion conditions, successfully yielded block copolymers [52]. A key to the success of these reactions was the isolation of the initiated species, which resulted in its separation from the dissociated phosphine. The initiated ruthenium complex was isolated by starting the polymerization in acidic organic solution, from which the reactive species precipitated. The solvent was removed, and the reactive species was washed with additional degassed solvent. The polymerization was completed under emulsion conditions (in water and DTAB), and additional blocks were generated by the sequential addition of the different monomers. This method of polymerization was successful for both the mannose/galactose polymer and for the mannose polymer with the intervening diol sequence (Fig. 16A,B). 

This reaction has been modified for various conditions, such as the application of microwave irradiation and the application of phosphine-containing polymer prepared from the ruthenium-catalyzed ring-opening metathesis polymerization of the norbornene. Most importantly, this reaction has been extended to the coupling of primary or secondary alkyl halides with aryl, vinyl, and even alkyl halide (or tosylate) 31,3o,3p,3y,3dd,3nn,4v,4x,6... 

Immobilization of homogeneous WGS catalysts was reported by Doi ct al. [41] for ruthenium carbonyl complexes modified with phosphine ligands as linkers to silica support material, resulting in a low activity of 0.5 h . RuClj-hydrate immobilized on silica was investigated by means of FT-IR. Upon recrystallization, the formation of dimeric [Ru(CO)3Cl2]2 and [Ru2(CO)i Cl4(H20)] was seen on the surface. Silica was also used to immobilize RuClj [42]. 

Ru/tppms catalysts exhibited excellent yields (98%) in the transfer hydrogenation of unsaturated aldehydes such as cinnamaldehyde or crotonaldehyde, to the corresponding unsaturated alcohols under mild reaction conditions (30-80°C), with HCOONa in an aqueous/organic two phase system. Similarly, ruthenium modified with the water soluble, air stable phosphine 100 (pta Table 5) is an effective catalyst for the chemoselective transfer hydrogenation of a,P-unsaturated aldehydes to unsaturated alcohols using formate in an aqueous/ organic two phase system. In contrast, Rh/pta afforded the cor-... 

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