Silver arsine complexes

Silver iodide derivatives of trialkyl-phosphines and -arsines were prepared in 1937 for comparison with their copper(I) iodide analogues.201 The preparations involved shaking the ligands with silver iodide dissolved in concentrated aqueous KI. The products were found to be tetramers and of similar structure to the Cu1 complexes. The Pr As silver complex was isomorphous with [Cul-AsEt3]4. Molecular weight determinations in a range of organic solvents showed that partial dissociation occurred in solution. 

Other arsenic-containing ligands reported include mixed donor species with S212 or N213,214 as the other donor atom. The ligand bis(carboxymethyl)(o-methylthiophenyl)arsine (24) contains S and As donors in a position suitable for chelation. Formation constants for its complexes with Ag1 are given in Table 30. The silver complexes of the m and p derivatives were insoluble under the conditions used and no data could be collected.212... 

A list of more common silver complexing agents includes thiosulfates, thiocyanates, sulfites, cyanides, ammonia and other amines, thiols, thiourea, thioacids, thioethers and alkali halides. Most are not practical as fixing agents because they fail to satisfy all the above criteria. Many find use as silver halide stabilizers (Section 59.2.1.8). These include thiocyanate, thiourea and other thioorganic compounds. These and other complexing agents such as cyclic imides, phosphines and arsines find use in silver halide diffusion transfer processes (Section 59.2.1.6). 

The arsine complex (Ph3As)AuOSiMea was similarly prepared. The tris-(phosphine)-copper and -silver complexes and the gold complexes are monomeric, with two-co-ordinate metal the mono- and bis-(phosphine)-copper and -silver siloxanes are oligomers (38) and (39), with bridging... 

Arsenic. Total arsenic concentration can be determined by reduction of all forms to arsine (AsH ) and collection of the arsine in a pyridine solution of silver diethyldithiocarbamate. Organoarsenides must be digested in acidic potassium persulfate prior to reduction. The complex that forms is deep red, and this color can be measured spectrophotometricaHy. Reduction is carried out in an acidic solution of KI—SnCl2, and AsH is generated by addition of 2inc. 

Although trialkyl- and triarylbismuthines are much weaker donors than the corresponding phosphoms, arsenic, and antimony compounds, they have nevertheless been employed to a considerable extent as ligands in transition metal complexes. The metals coordinated to the bismuth in these complexes include chromium (72—77), cobalt (78,79), iridium (80), iron (77,81,82), manganese (83,84), molybdenum (72,75—77,85—89), nickel (75,79,90,91), niobium (92), rhodium (93,94), silver (95—97), tungsten (72,75—77,87,89), uranium (98), and vanadium (99). The coordination compounds formed from tertiary bismuthines are less stable than those formed from tertiary phosphines, arsines, or stibines. 

Rather than utilizing complete transmetallation reactions, mixed metal silver(i) aryl complexes 8-11 were obtained from the reaction of soluble silver salts with arylgold(i) complexes possessing ancillary phosphine or arsine ligands, as shown in Scheme l.29,30... 

Although reports on silver(i) cr-alkynyl complexes have appeared for more than a century, the number of examples was still very limited prior to the past decade, and many of them were referred to as insoluble homoleptic polymeric [Ag(C=CR)]oo. Molecular alkynylsilver(i) complexes were often heteroleptic in nature and were achieved commonly through the stabilization by an extra coordination with strong cr-donor ligands such as amines, phosphines, and arsines. 

Kneen (4, 31) prepared a series of copper(I), silver(I) and gold(I) complexes containing olefinic tertiary phosphines and arsines for several reasons ... 

Ligand exchange reactions have been used to prepare mercury(II) trialkylarsine complexes.202 Reaction of AgN03-AsMe3 with mercury halides gave the mercury arsine and silver halide (equations 10 and 11). The silver nitrate complex was not characterized. 

Silver salts of triphenylarsine and triphenylstibine have also been prepared. When silver trifluoroacetate was added to a methanol-water solution of triphenylarsine, a change due to complexation was observed in the UV spectrum. The trifluoroacetate was assumed to be completely dissociated and a 1 1 complex with the arsine formed. The stability constant at 25 °C was determined as log / i = 5.7-5.8.203... 

In phosphine and arsine complexes of the type LM(diketonate) (M = Ag, Au) and CuL2(dike-tonate), t]2 oxygen bonded diketonate ligands occur in the copper(I) and silver(I) derivatives but the gold(I) analogues feature the jj, carbon bonded form.483... 

As VIS Arsenic in the sample is converted to arsine, which is evolved and then complexed with silver diethyldithiocar-bamate. The intensity of the color of the complex is measured at 510-525 nm. Applicable to 0.001-0.1 mg L-1 in surface and waste waters. Interference from Sb may be important. Ag, Cr, Co, Mo, Ni, Hg, and Pt at concentrations <5 mg L-1 do not interfere. 93... 

The Shibasaki cychzation of mc.vo-cyclohexa-1,4-dienes in the presence of a chiral palladium complex and silver carbonate in l-methyl-2-pyrrolidinone is probably the first example of an enantioselective Heck reaction (Scheme 10.34).60 The enantiomeric excess could be slightly improved by replacing the chiral phosphine ligand BINAP with the corresponding less coordinating arsine ligand, as well as replacing silver carbonate with silver phosphate.61,62... 

Interferences Metals or salts of metals such as chromium, cobalt, copper, mercury, molybdenum, nickel, palladium, and silver may interfere with the evolution of arsine. Antimony, which forms stibine, is the only metal likely to produce a positive interference in the color development with the silver diethyldithiocarbamate. Stibine forms a red color with silver diethyldithiocarbamate that has a maximum absorbance at 510 nm, but at 535 to 540 nm, the absorbance of the antimony complex is so diminished that the results of the determination would not be altered significantly. 

AsAgFsSi6, Arsenate, hexafluoro-, bis-(cycZo-octasulfur)silver(l -h), 24 74 AsBrsFgS, Arsenate, hexafluoro-, tribromo-sulfur(IV), 24 76 AsQH, Arsine, dimethyl-molybdenum complex, 25 169 AsCigHis, Arsine, triphenyl-chromium complexes, 23 38 ASC24H10, Arsonium, tetraphenyl-... 

Arsine bubbled into the solution in the cuvette, reacting with silver diethyldithiocarbamate to form a colored complex compound according to the following equation ... 

A 25-mL solution containing 500 ppb of arsenic (Ag3+) was stirred with 1 g of borohydride-form A-26 anion-exchange resin. The reaction vessel was connected to an absorption tube filled with a solution to absorb the volatile hydride of arsenic (i.e., arsine, AsH3). The absorption solution is made by dissolving 1 g of silver diethyldithiocarbamate (SDDC) in 200 mL of pyridine. The volatile arsine is complexed with the SDDC solution to give a colored solution, whose absorbance is... 

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