Phosphine metals

ALKYLHALOPHOSPHINES, ALKYLPHOSPHINES tert-BUTYL PEROXOPHOSPHATE ESTERS iV-CHLORINATED PHOSPHORUS AMIDES HALOPHOSPHINES, METAL PHOSPHINATES METAL PHOSPHORUS TRISULFIDES NON-METAL OXIDES, NON-METAL SULFIDES PHOSPHINES, PHOSPHORUS ESTERS... 

Ci Hg P. In terms of the shift in CO stretching frequencies in phosphine metal carbonyl complexes, PH3 is less basic (or more 7r-acid) than trialkyl or triaryl phosphines (7, 8, 9).) The results, reported in this chapter, lead to the following significant conclusions. 

It is generally accepted that C02 is somewhat unreactive towards transition metal complexes and that the metal C02 linkage is favoured by a nucleophilic metal centre such as a tertiary phosphine metal(O) moiety. 

METAL NITRATES Esters, or Phosphorus, or Tin(II) chloride METAL NITRATES Metal phosphinates METAL PERCHLORATES Calcium hydride PERCHLORATES Reducants... 

The fragmentation patterns of a number of phosphine-metal carbonyl complexes have been reported 164). Complexes of bis(diphenylphos-phino)ethane (diphos) appear to lose ethylene to give ions of the type (Ph2P)2Mo+. In contrast to thermal decomposition by loss of phosphine,... 

Aluminum powder Aluminum alkyls Grinding Heating Carboxylic acid chlorides Ethers Tertiary amines Tertiary phosphines Metal chlorides... 

Other neutral fragments eliminated in the fragmentation processes of tris-(dimethylamino) phosphine metal carbonyl complexes appear to contain phosphorus-hydrogen bonds, e. g. 

Other synthetic routes reported involve the interactions of trifluoro-phosphine metallates and iodine (method E), displacement of carbon monoxide, alkenes, etc. by PF3 from the corresponding halide complexes (method F), addition of PF3 to dinuclear halogeno-bridged PF3 complexes at low temperatures (method G), and treatment of a metal hydrido- PF3 complex with iodoform (method H). 

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

Pure phosphine-metal atom studies with the early transition metals have been lacking. The only complex prepared this way prior to 1978 was Cr(Pp3)6. King and Chang, with the unique aminophosphine systems Me2NPF2 and MeN(Pp2)2, have generated a variety of new homoleptic M-(L) systems (see Homoleptic Compound). The codeposition of Cr vapor with these ligands yields the complexes shown ... 

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. 

Interest in the chemistry of phosphines metallated at carbon has also been... 

Table 2 Relative rates of aryl group interchange between triphenylphosphine and tris-para-tolylphosphine cat yzed by group 8 transition metals. Reaction conditions 1000 ppm of metal catalyst phosphine metal mole ratio = 20 100 psi ofH2 C3H6(l l)...

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. 

The important preparative methods, namely, reduction of phosphine metal halide complexes and the hydride-transfer and reverse carbonylation reactions, were discussed in Section I,B,2 and 3. Other routes are incidentally discussed below. 

A large number of clusters of Group VIII and Group IB metals have been prepared in which a variety of phosphines are the principal ligands. These clusters are listed in Table IX. The phosphine clusters have been prepared by a wide variety of methods as can be seen from Table IX, and no general methods of preparation can be designated for these compounds. Most of them involve either the reaction of a zero-valent phosphine metal compound, or reduction of a higher valent compound. The phosphine clusters listed in Table IX have all been reported since 1966, and the structure of only one of these compounds has been... 

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