Silver bimetallic complexes

There are two structurally characterized examples in which an arylpalladium(ll) coordinates to silver(l) in a type 11 fashion (Scheme 10). First, Kickham and Loeb [40] reported that an attempt to abstract the chloride ligand in a palladated thiacyclo-phane with two equivalents of silver(l) triflate unexpectedly resulted in the formation of a bimetallic complex in which the silver(l) ion is encapsulated by three oxygen atoms and an interaction with the Pd-C bond. Then, Braunstein et al. [41] synthesized a remarkable one-dimensional coordination polymer by reacting the phosphanyl immolate palladium complex depicted in Scheme 10 (bottom) with silver(l) triflate. 

Bimetallic complexes formed using a lanthanide tris (3-diketonate and silver 3-diketonate are useful shift reagents for soft Lewis bases such as alkenes, aromatics, phosphines, and halogenated compounds.Chiral lanthanide tris (3-diketonates of tfc and hfc are used in forming the binuclear reagents. A variety of silver 3-diketonates have been evaluated, but only the silver chelate of 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione [Ag (fod)] is commercially available. The mixture forms a tetrakis chelate anion to which the silver is ion paired ([Ln (P-dik)4 ]Ag" "). In the bimetallic reagent, the silver binds to the soft Lewis base while the paramagnetic lanthanide ion causes perturbations in the chemical shifts that account for the enantiomeric discrimination. 

The paper discloses one example of enantioselective variant. The catalytically active species is a cationic bimetallic complex generated from the (/ )-xylyl-SDP-gold pre-catalyst C5 after addition of a silver salt. The expected polycyclic product could be isolated in good yield, with 82% enantiomeric excess. 

Siloxane compounds, in vitreous silica manufacture, 22 414 Siloxane materials, 20 240 Siloxane oligomers, in silicone polymerization, 22 555-556 Siloxanols, silylation and, 22 703 Silsesquioxane hybrids, 13 549 Silsesquioxanes, 15 188, 22 589-590 SilvaGas process, 3 696, 697 Silver (Ag), 22 636-667. See also Silver compounds. See Ag entries Argentothiosulfate complexes Batch desilverizing Lead-silver alloys Palladium-silver alloy membranes analytical methods for, 22 650-651 applications of, 22 636-637, 657-662 as bactericide, 22 656, 657, 660 barium alloys with, 3 344 in bimetallic monetary system, 22 647-648 in cast dental gold alloys, 8 307t coke formation on, 5 266 colloidal precipitation color, 7 343t colloidal suspensions, 7 275 color, 7 334, 335... 

Reduction of Double Complexes. Except for Ag/Au bimetallic nanoparticles, bimetallic nanoparticle dispersions containing Ag have not been studied extensively. One of the possible reasons is that an Ag1 ion readily reacts with a halide ion to produce water-insoluble silver halide. Also, many other water-soluble metal salts other than halides are not as suitable as precursors for the production of metallic particles by mild reduction. 

Bimetallic gold-silver complexes may be prepared from gold bis(ylide) species such as [Au(CH2PPh3)2]ClC>4 and AgC104 (leading to neutral clusters, equation 54) or... 

A recent example [31] from Falvello et al. on bimetallic, pyrazolate-bridged complexes of platinum(II) and palladium(II) is instructive (Scheme 8). These two compounds exhibit differentiated behavior in the presence of silver(I) perchlorate the platinum complex binds silver through two donor-acceptor metal-metal bonds supplemented by silver-tolyl n interactiOTis, while the palladium complex binds silver through the 71-electron density of the pyrazolate ligands. 

Using silver(I)-bis(oxalato)palladate(II) complex, Rhee et al. reported synthesis of ultrafine Ag-Pd bimetallic nanoparticles. The advantage of this complex, which contains both metal ions, is prevention of formation of silver halides. Moreover, the oxalate ligand rapidly decomposes by light irradiation or chemical reduction. It was demonstrated that the particle size distribution is dependent on the Ag/Pd ratio [46],... 

Self-assembly of a diruthenium precursor 285 as a bimetallic connector with tris-pyridyl ligand syntone 241 in the presence of silver(l) ions by Scheme 4.35 afforded a cationic TP (arene)ruthe-ninm Rne Ls La coordination capsule 540 [36]. This capsule encapsulates palladium and platinnm(ll) acetylacetonates to give the corresponding 1 1 cage complexes [36]. In the platinum-... 

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