Phosphines metal complexes

Substitution of CO in the perfluoroalkyl metal carbonyl derivative provides a synthetic route to perfluoroalkyl mixed-carbonyl trifluoro-phosphine metal complexes (method D). 

Well glass plates were loaded with different phosphines, metal complexes, aniline, and 1,3-cyclohexadiene. A coloro-metric assay for unreacted aniline (a red color arising from the acid catalyzed reaction of aniline with furfural) was used to screen successfiil catalysts, that is, those that did not turn red. Catalysts derived from [Pd(7r-allyl)Cl]2 and PPhs were most active. Increasingly, such high-throughput methods are being used in catalyst discovery and optimization. 

In contrast, many chiral phosphine-metal complexes have been investigated in the enantioselective hydrogenation of functionalized ketones because of the synthetic significance of the corresponding alcoholic products [5]. A high catalytic activity and an excellent level of enantioselectivity have been achieved by means of chiral phosphine-Ru complexes, as shown below. The presence of a functional group dose to the carbonyl moiety effidently accelerates the reaction and also controls the stereochemical outcome. The heteroatom-metal interaction is supposed to effectively stabilize one of diastereomeric transition states and/or key intermediates in... 

Recently it has become clear that tertiary phosphine-metal complexes are reactive and liable to undergo carbon-phosphorus bond scission. The reaction between the C— P " bond and the transition metal to which the tertiary phosphine is bound has profound implications on homogeneous catalysis, particularly on the mode of homogeneous catalyst deactivation in hydroformylation (Rh- and Co-catalyzed) and various other hydrogenation/dehydrogenation reactions, including asymmetric hydrogenation. 

Other ligand environments (e.g. cyclopentadienyl or phosphine metal complexes) have proved more adequate for detailed investigations of the hydrogenation of N-heterocycles. The groups of Fish [91], Sanchez-Delgado [99] and Rosales [100] have provided extensive studies including kinetic data, deuteration experiments, detailed NMR studies, isolation of important intermediates, and some theoretical calculations. 

Hydroformylation and Hydrogenation Catalyzed by Perfluoroalkylated Phosphine-Metal Complexes... 

The phosphine metal complexes now finding application in homogeneous catalysis are those of the tertiary organic phosphines. They were discovered around the middle of the last century and their ability to combine with heavy metal salts noted almost immediately, but the application of their metal complexes to homogeneous catalysis came only after the lapse of about 100 years. 

The early development of aromatic phosphine chemistry took place during the last quarter of the nineteenth century mainly in Michaelis s school.He prepared dichloro(phenyl)phosphine by the passage of the mixed vapours of benzene and phosphorus trichloride through a red hot porcelain tube. This was quickly followed by the preparation of phenylphosphine, dialkylphenylphosphines, and triphenylphosphine. This latter phosphine was destined some 75 years later to become one of the most important phosphines in the development of homogeneous catalysis by phosphine metal complexes. Michaelis obtained it by the reaction of sodium with dichloro(phenyl)phosphine or phosphorus trichloride and bromobenzene in boiling ether.The development of aromatic phosphorus chemistry rapidly overtook that of their intractable aliphatic analogs. It was well established by the 1920s whereas the aliphatic had to await the... 

The involvement of hydroperoxy metal complexes in oxidation reactions has been variously postulated and discussed. Metal hydroperoxides and alkylperoxides can be potentially prepared from hydrogen peroxide or alkylperoxides. Alternately, it is apparent that since a dioxygen molecule coordinated to a low-valent phosphine metal complex is an... 

Phosphines. Polymeric phosphines exhibit strong metal-binding properties. Nonpolymeric phosphines, in particular triphenylphosphine, are employed as ligands for cobalt and rhodium in hydroformylation catalysts used in plasticizer manufacture. Extensive efforts have been made to attach phosphine-metal complexes to polymers in order to facilitate catalyst recovery and enhance selectivity... 

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