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Phosphine-silver complexes

This system also worked well in ionic liquids.518 Li etal. found silver-phosphine complexes to promote aldehyde-alkyne coupling in water. When triphenylphosphinesilver chloride was used as a catalyst in water, the only detected product was the aldehyde addition product instead of the adduct derived from imine (Scheme 111).519... [Pg.478]

Table 27 Coupling Constants for some Silver Phosphine Complexes (Hz)... Table 27 Coupling Constants for some Silver Phosphine Complexes (Hz)...
Most of the examples given in the preceding text relied on silver phosphine complexes as catalysts. The. Mrgensen group examined the use of cinchona-derived ligands in the silver fluoride-catalyzed reaction of aromatic iminoesters 103 with methylacrylate (27). Yields were excellent, but enantioselectivities were only in the... [Pg.65]

With the relative air and water stability of silver phosphine complexes in mind, the Frost and Weller groups reported the use of a silver(I) carborane triphenylphosphine complex as a catalyst for the aza-Diels-Alder reaction.82,83 These unique catalyst complexes were able to catalyze the reaction of Danishefsky s diene (195) with 196 in... [Pg.74]

In analogy t 0 the Cu(II) complex systems, the silver(I) -catalyzed aldol reaction is also proposed to proceed smoothly through a Lewis acidic activation of carbonyl compounds. Since Ito and co-workers reported the first example of the asymmetric aldol reaction of tosylmethyl isocyanide and aldehydes in the presence of a chiral silver(I)-phosphine complex (99,100), the catalyst systems of sil-ver(I) and chiral phosphines have been applied successfully in the aldol reaction of tin enolates and aldehydes (101), Mukaiyama aldol reaction (102), and aldol reaction of alkenyl trichloroacetates and aldehydes (103). In the Ag(I)-disphosphine complex catalyzed aldol reaction, Momiyama and Yamamoto have also examined an aldol-type reaction of tin enolates and nitrosobenzene with different silver-phosphine complexes (Scheme 15). The catalytic activity and enantioselectivity of AgOTfi(f )-BINAP (2 1) complex that a metal center coordinated to one phosphine and triflate were relay on solvent effect dramatically (Scheme) (104). One catalyst system solves two problems for the synthesis of different O- and AT-nitroso aldol adducts under controlled conditions. [Pg.2216]

Codeposition of silver vapor with perfluoroalkyl iodides at -196 °C provides an alternative route to nonsolvated primary perfluoroalkylsilvers [272] Phosphine complexes of trifluaromethylsilver are formed from the reaction of trimethyl-phosphme, silver acetate, and bis(trifluoromethyl)cadmium glyme [755] The per-fluoroalkylsilver compounds react with halogens [270], carbon dioxide [274], allyl halides [270, 274], mineral acids and water [275], and nitrosyl chloride [276] to give the expected products Oxidation with dioxygen gives ketones [270] or acyl halides [270] Sulfur reacts via insertion of sulfur into the carbon-silver bond [270] (equation 188)... [Pg.716]

Linear S-Au-S (but non-linear Au-S-C) is found in PhAs+Au(SCN)2 [96] related phosphine complexes (R3P) AuSCN have been made (section 4.10.3). Sulphate and thiosulphate bind through sulphur Na3Au(S203)2.2H20 has linear 2-coordinate gold in contrast to tetrahedral coordination of silver by sulphur and oxygen. [Pg.297]

Gold, unlike silver, forms a wide range of cluster complexes [184] where the average oxidation state of the metal is below +1 they may be synthesized by reduction of gold(I) phosphine complexes ... [Pg.319]

An extension of the research on silver complexes with Lewis base-functionalized mono(A-heterocyclic carbene) ligands has been made toward the better-studied and stronger coordinating phosphine systems. The reaction of a diphenylphosphine-functionalized imidazolium salt with silver oxide in dichloromethane affords a trinuclear silver carbene complex 50, as confirmed by electrospray-ionization mass spectrometry.96,97 Metathesis reaction of 50 in methanol using silver nitrate gives 51 in 33% yield. The crystal structures of 51 were found to be different when different solvents were used during crystallization (Scheme 12).97 One NO3- anion was found to be chelated to... [Pg.213]

In a joint study by Schmidbaur and Raubenheimer, several phosphine carboxylates and sulfonates of gold and silver were tested as catalysts for the hydration of nonactive alkynes [99]. While the gold complexes showed high activity for these reactions, analogous silver (I) complexes were not active in them. This different behavior was due to the fact that gold cations are weaker acceptors for their ligands and counterions than silver (I) cations (Figure 8.3). [Pg.452]

A variety of silver(I) complexes of phosphines are known. For triaryl and mixed alkyl-aryl tertiary phosphines, stoichiometries of from 1 1 to 1 4 have been reported, whereas with trialkylphosphines most of the isolated complexes were of 1 1 stoichiometry.169... [Pg.798]

Table 26 IR Data for Some Silver Thiocyanate Phosphine Complexes... Table 26 IR Data for Some Silver Thiocyanate Phosphine Complexes...
One area of silver chemistry that has received much recent attention is the synthesis of multinuclear aggregates.315 Anionic metal dithiolato complexes such as K M(S2C202)2 were found to form adducts with silver(I) phosphines. In these complexes, the inert cations (K+) that accompanied the metallothio anions could be readily substituted by coordinatively unsaturated silver phosphines Ag(PR3)2. For dithiooxalto complexes this led to the isolation of a remarkable range of linkage isomers (34)-(37) 316,317... [Pg.815]

Table 45 Some Properties of Polynuclear Dithiolate Complexes Containing Silver Phosphines... Table 45 Some Properties of Polynuclear Dithiolate Complexes Containing Silver Phosphines...

See other pages where Phosphine-silver complexes is mentioned: [Pg.198]    [Pg.159]    [Pg.474]    [Pg.121]    [Pg.111]    [Pg.115]    [Pg.198]    [Pg.159]    [Pg.474]    [Pg.121]    [Pg.111]    [Pg.115]    [Pg.223]    [Pg.112]    [Pg.921]    [Pg.929]    [Pg.929]    [Pg.930]    [Pg.942]    [Pg.943]    [Pg.943]    [Pg.944]    [Pg.945]    [Pg.946]    [Pg.949]    [Pg.953]    [Pg.963]    [Pg.964]    [Pg.977]    [Pg.982]    [Pg.211]    [Pg.227]    [Pg.156]    [Pg.180]    [Pg.92]   
See also in sourсe #XX -- [ Pg.74 , Pg.198 ]

See also in sourсe #XX -- [ Pg.137 , Pg.145 ]




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