Silver complexes anionic

Silver chloride is readily soluble in ammonia, the bromide less readily and the iodide only slightly, forming the complex cation [Ag(NH3)2]. These halides also dissolve in potassium cyanide, forming the linear complex anion [AglCN) ] and in sodium thiosulphate forming another complex anion, [Ag(S203)2] ... 

The preparation of a series of transition metal complexes (Co. Ni. Pd. Pt, Ir. Au. Cu. Ag) with ambident anion (70) and phosphines as ligands has been reported recently (885). According to the infrared and NMR spectra the thiazoline-2-thione anion is bounded through the exocyclic sulfur atom to the metal. The copper and silver complexes have been found to be dimeric. 

These compounds perform a dual function in synthesis procedures. The introduction of a complex anion assists in the stabilization of the desired product and the generation of unique intermediates by chloride displacement, eg, silver hexafluorophosphate, AgPF, forms adducts with neutral diamagnetic organometaHics which can act as controUed sources of highly reactive cations (29). Silver hexafluoroantimonate, AgSbF, is an electrophilic... 

The perfluoroalkylsilver complexes exist in a dynamic equilibrium in solution with solvated silver ion and anionic perfluoroalkylsilver complexes such as Ag[CF(CF5) r [277] The triflnoromethylated silver complex, Ag(CF3)4 , is prepared via reaction of bis(trifIuoromethyl)cadmium with silver nitrate in acetoni trile [278]... 

The first and third examples illustrate a nuance of the naming rules. Iron and silver in anionic complexes are named by their Latin roots,/err- and argent-, from which their symbols (Fe and Ag) are derived. Metals taking their Latin names in anionic coordination complexes are listed in Table 20-4. 

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... 

The complexation of anionic species by tetra-bridged phosphorylated cavitands concerns mainly the work of Puddephatt et al. who described the selective complexation of halides by the tetra-copper and tetra-silver complexes of 2 (see Scheme 17). The complexes are size selective hosts for halide anions and it was demonstrated that in the copper complex, iodide is preferred over chloride. Iodide is large enough to bridge the four copper atoms but chloride is too small and can coordinate only to three of them to form the [2-Cu4(yU-Cl)4(yU3-Cl)] complex so that in a mixed iodide-chloride complex, iodide is preferentially encapsulated inside the cavity. In the [2-Ag4(//-Cl)4(yU4-Cl)] silver complex, the larger size of the Ag(I) atom allowed the inner chloride atom to bind with the four silver atoms. The X-ray crystal structure of the complexes revealed that one Y halide ion is encapsulated in the center of the cavity and bound to 3 copper atoms in [2-Cu4(//-Cl)4(//3-Cl)] (Y=C1) [45] or to 4 copper atoms in [2-Cu4(/U-Cl)4(/U4-I)] (Y=I) and to 4 silver atoms in [2-Ag4(/i-Cl)4(/i4-Cl)] [47]. NMR studies in solution of the inclusion process showed that multiple coordination types take place in the supramolecular complexes. 

Aroyl and related salts (ArCO, AlkCO ) and stable carbenium ion salts (e.g. Ar3C ) of complex anions MtX . i can be synthesised essentially by two routes, silver salt double decomposition, and direct combination ... 

The catalysis of the cleavage of carbon-halogen bonds by complexation with metal ions such as silver or mercuric ion is a well-known phenomenon. The compounds susceptible to this action are alkyl halides capable of forming car-bonium ions. The complexed anions such as in mercuric nitrate, mercuric perchlorate, or hydrated mercuric ion do not exhibit a simple relationship between their effect on the total rate and on the relative distribution of products stemming from water or the anion. This evidence is indicative of the following catalytic mechanism ... 

The first silver(I) poly(pyrazolyl)borate complexes were reported in 1975.150 Since then, a number of silver complexes of the type Ag(L)(R B(pz)4 ) have been isolated and characterized.151,152 They were prepared by the reaction of the poly(pyrazolyl)borate anions with silver(I) salts, usually the nitrate, in the presence of donor ligands, L, and were isolated as white, thermally stable compounds. In most cases they were either insoluble, or at best only sparingly soluble, in common organic solvents. 

Table 50 Stability Constants (log ( 2) for the Formation of the Complex Silver Halide Anions AgXj in Various Solvents...

C. Supramolecular Gold-Silver Complexes Built with Metallic Cationic and Anionic Counterparts... 

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