Silver I Complexes

Ag(I) tends to form complexes with a number of ligands. Of particular interest are those formed with iodide and the copper(ll) cationic/silver(l) anionic complexes. 

The complex can be analysed by titrimetric determination of iodine and/or gravimetric determination of Ag as Agl. 

Weigh out accurately about 0.4 g of your preparation into a round bottom flask fitted with a joint. Fit an upright condenser and add 40 cm of dilute nitric acid. Warm the 

Wash the precipitated Agl on the sintered glass crucible with very dilute HNO3CA cm cone. + 200 cm HjO) and dry to a constant weight at I40 C. Calculate the percentage of 

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Pyridine bases are well known as ligands in complexes of transition metals, and it might well be anticipated that the equilibrium constants for the formation of such complexes, which are likely to be closely related to the base strength, would follow the Hammett equation. Surprisingly, only very few quantitative studies of such equilibria seem to have been reported, and these only for very short series of compounds. Thus, Murmann and Basolo have reported the formation constants, in aqueous solution at 25°, of the silver(I) complexes... 

It forms a stable silver(I) complex in acetonitrile, in keeping with the ability of MeCN to solvate Ag+ in the presence of water, disproportionation occurs [62],... 

Roland et al. obtained 23% ee in the addition of Et2Zn to cyclohexenone using the silver(I) complex 78 having a chiral backbone and methyl groups on the nitrogen atoms. This complex acts as an efficient carbene transfer agent towards Cu(OTf)2. The conjugate addition proceeds rapidly in toluene at 0 °C (Scheme 52). 

Based on the fact that pi-acids interact with the trinuclear gold] I) pi-bases, TR(carb) and TR(bzim), the trinuclear 3,5-diphenylpyrazolate silver(I) complex was reacted with each. Mixing [Au3(carb)3] or [Au3(bzim)3] with [Ag3(p,-3,5-Ph2pz)3] in CH2CI2 in stoichiometric ratios of 1 2 and 2 1 produced the mixed metal/mixed ligand complexes in the same gold-silver ratios. The crystalline products were not the expected acid-base adducts. It is suspected that the lability of the M-N bond (M=Au, Ag) in these complexes results in the subsequent cleavage of the cyclic complexes to produce the products statistically expected from the stoichiometry of materials used [74]. As a result of the lability of Au-N and Ag-N bonds, and the stability of... 

Archibald, S.J., Alcock, N.W., Busch, D.H. and Whitcomb, D.R. (2000) Synthesis and characterization of silver(I) complexes with C-AIkyl functionahzed N,f/-Diphenylamidrnates Tetrameric and trrmeric structural motifs. Journal of Cluster Science, 11, 261—283. 

Uson, R., Laguna, A., Fernandez, E.J., Mendia, A. and Jones, P.G. (1988) (Polyhalophenyl)silver(I) complexes as arylating agents crystal structure of [(p-2,4,6-C6F3H2)(AuPPh3)2]C104. 

Mononuclear silver(I) complexes with nitrogen ligands can have several coordination numbers, the simplest is dicoordinated and compounds of the type [AgL2]+ occur for a variety of ligands... 

Three-coordinate silver(I) complexes with nitrogen donor ligands are of the form [AgXL2] (L = 3-ferrocenylpyridine, X = OTf L = 3- or 4-NCPy, 2-, 3-, or 4-NCC6H4NH2, X = N03). 

Other tri-coordinate silver(I) complexes are the bridging pyrazolate complexes such as [Ir(775-C5Me5)(pz)3Ag(PPh3)], [Ir(//5-C3Mc5)(pz)3 Ag(PPh3) 2]BF4, and [Ir(j 5-C5Me5)(PPh3)-... 

Silver(I) complexes are known with the tris(pyrazolyl)borate [HB(pz)3] and the methyl, phenyl, bromo, or trifluoromethyl-substituted derivatives. The structure of the silver tri(pyrazolyl)borato species has been a puzzle since it was first reported.385,386 It was suggested that the structure could be oligomeric, but recently the crystal structure of the compound [Ag HB(3,5-Me2pz)3 ]2 shows that it has a dimeric structure387 where the silver(I) centers are tricoordinated by a bidentate arm of one ligand and a monodentate arm of the other ligand (29). The related complexes [Ag HB(4-Brpz)3 ]2, [Ag HB(4-Mepz)3 ]2, [Ag HB(3,5-Me2pz)3 ]2, [Ag HB(3-Mepz)3 ] , [Ag B(pz)4 ], and... 

Other polydentate ligands are polyamines and related ligands. Stability constants of silver(I) complexes with polyamines in dimethyl sulfoxide,419 A-methyl-substituted 4-methyldiethylene-triamines,420 or ethylene- or N- or C-methylated ethylenediamine in aqueous solution have been reported.421 The structure of the silver 1,3-diaminopropane complex, [Ag NH2(CH2)3NH2 ]-C104,422 and complex formation with 1,4-diaminobutane and 1,5-diaminopentane have been reported.423 A dinuclear silver(I) compound with ethylenediamine [(enH)Ag(en)Ag(enH)2]4+ has... 

Silver(I) complexes with macrocyclic nitrogen ligands are also very numerous. Mono- or homodi-nuclear silver-containing molecular clefts can be synthesized from the cyclocondensation of functionalized alkanediamines or triamines with 2,6-diacetylpyridine, pyridine-2,6-dicarbalde-hyde, thiophene-2,5-dicarbaldehyde, furan-2,5-dicarbaldehyde, or pyrrole-2,5-dicarbaldehyde in the presence of silver(I).486 97 The clefts are derived from bibracchial tetraimine Schiff base macrocycles and have been used, via transmetallation reactions, to complex other metal centers. The incorporation of a range of functionalized triamines has provided the conformational flexibility to vary the homodinuclear intermetallic separation from ca. 3 A to an excess of 6 A, and also to incorporate anions as intermetallic spacers. Some examples of the silver(I) complexes obtained are shown in Figure 5. 

Several silver(I) complexes of the macrocyclic Schiff base derived from the [2+2] condensation of terephthalaldehyde and 3-azapentane-1,5-diamine or A,A -bis(3-aminopropyl)methylamine have been described.509,510 The reaction of 2,ll-diaza-difluoro-m-[3,3]-cyclophane with 2,6-bis (bromomethyl)pyridine lead to the 3 + 3 addition product, which gives a complex with two silver... 

Figure 6 Ligands which form silver(I) complexes with helical structures.

Polymeric silver(I) complexes have also been achieved with cyanosulfanes, they react with silver(I) according to Equation (5). 

Figure 7 Rigid nitrile ligands which form polymeric silver(I) complexes.

Silver(I) complexes with polyamines also form molecular aggregates, thus hexamethylenetetramine yields 2D and 3D coordination networks,613 polymeric chains are obtained with diethylene-triamine, tris(2-aminoethyl)amine, or A,A -bis(aminoethyl)propane-l,3-diamine,426 and 2D networks are formed with thiocyanate and bridging polyamines.61... 

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