Mono complexes silver

Reactions in Water.—The ultrasonic absorption technique has been applied to silver(i) thiosulphate in solutions of which the predominant species is the ion [Ag(S203)2] . Both of the relaxation effects observed over the 15—230 MHz frequency range were attributed to the stepwise mutual approach of [AgS203] and [SaOal - with the elimination of co-ordinated water. At 25 °C the rate constant for this association reaction is 1.0 x 10 1 mol s, which is close both to the value calculated on the basis of the process being essentially diffusion controlled and to the literature value for the reaction of a second molecule of phen with the mono-complex [Ag(phen)]+. The authors favour an associative mechanism for these reactions of Ag+, with the bound ligand having essentially no effect on kr. 

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. 

Imine-functionalized mono-A-heterocyclic carbene ligands were complexed to the silver(i) center to form the corresponding [Ag(carbene)2][AgX2] complexes 41-43 (Figure 18).88-90... 

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... 

Owing to their instability at room temperature, complexes of straight-chain mono-olefins with copper(I) halides and with silver nitrate have been characterised mainly by distribution studies in solution, and, in the... 

The reactions of silver(I) with 1,5-diphenyl thiocarbazone (56 dithizone = HaDz) by comparison to thiosemicarbazones have been thoroughly investigated.442,444 Dithizone has for many years been used as a colorimetric reagent for trace metal ions. Its metal complexes are of two types, the so-called primary and secondary dithizonates. Primary dithizonates are generally formed at low pHs where the ligand becomes mono depronated (pA = 4.5) but retains the NH proton. Secondary dithizonates are formed in the presence of an excess of metal and/or at higher pH values where the ligand becomes fully deprotonated. Since it has been estimated that for free dithizone pK2 > 15, the second proton obviously becomes labilized in the presence of metal ions. 

Peroxydisulfate oxidations have also been used to prepare a variety of pyridine mono- and di-carboxylic add silver(II) complexes.496 All these compounds were orange-red in colour and sparingly soluble to insoluble in most solvents, including water. 

The oxidative effects of silver(II) complexes of pyridine carboxylates have been studied for a variety of substrates. With ar-amino acids, a rapid reaction occurred at 70 °C in aqueous solution with bis(pyridyl-2-carboxylato)silver(II). 4 The product was the next lower homologous aldehyde and yields were generally greater than 80%. Other substrates included primary and secondary amines, alcohols, monosaccharide derivatives, alkenes, arylalkanes and arylalkanols.90 Only minor differences were detected in efficiencies when 2-, 3- or 4-mono-, or 2,3-di-carboxylates were used as the oxidant. 

Mono and bis 2,2 -bipyridyl and 1,10-phenanthroline complexes of silver(II) have been isolated as red-brown crystals by either peroxydisulfate, anodic or ozone oxidation techniques.497,519 No tris-chelated species have been substantiated,497 although it is worth noting that a 2,2, 2"-terpyridyl bis complex has been isolated and claimed to be a six-coordinate... 

Several cyanodithioformates are mentioned in ref. 1. The coordination chemistry of monothio-carboxylates deals almost exclusively with thioacetates and thiobenzoates. Structures of several monothiobenzoates are based on IR data.42 Those, however, of the copper(I) and silver(I) complexes are doubtful. They are probably polymeric and of the same structural class as the mono- and di-thiocarbamates43-45... 

Aza complexes, with mono-Cp Ti(IV), 4, 417 Aza-crown-substituted ruthenocenes, preparation, 6, 635-636 Aza-Diels-Alder reactions, via silver catalysts, 9, 567... 

Imidazolium ligands, in Rh complexes, 7, 126 Imidazolium salts iridium binding, 7, 349 in silver(I) carbene synthesis, 2, 206 Imidazol-2-ylidene carbenes, with tungsten carbonyls, 5, 678 (Imidazol-2-ylidene)gold(I) complexes, preparation, 2, 289 Imidazopyridine, in trinuclear Ru and Os clusters, 6, 727 Imidazo[l,2-a]-pyridines, iodo-substituted, in Grignard reagent preparation, 9, 37—38 Imido alkyl complexes, with tantalum, 5, 118—120 Imido-amido half-sandwich compounds, with tantalum, 5,183 /13-Imido clusters, with trinuclear Ru clusters, 6, 733 Imido complexes with bis-Gp Ti, 4, 579 with monoalkyl Ti(IV), 4, 336 with mono-Gp Ti(IV), 4, 419 with Ru half-sandwiches, 6, 519—520 with tantalum, 5, 110 with titanium(IV) dialkyls, 4, 352 with titanocenes, 4, 566 with tungsten... 

Molybdenum trioxide, intercalation into, 12, 823 Molybdocenes, as anticancer agents, 1, 892 MOMNs, see Metal-organometallic coordination networks Monisocyanides, with silver(I) complexes, 2, 223 Monitoring methods, kinetic studies, 1, 513 Mono(acetylacetonate) complexes, with Ru and Os halfsandwich rf-arenes, 6, 523 tj2-Monoalkene monodentate ligands, with platinum divalent derivatives, 8, 617 tetravalent derivatives, 8, 625 theoretical studies, 8, 625 zerovalent derivatives, 8, 612... 

Monomethyl pyrazolato complexes, with Ti(IV), 4, 335 Mono(A-heterocyclic carbene) ligands, in silver(I) complexes, 2, 210... 

Silver(n) and Silvery hi).—The cationic complex bis-(2,2, 2"-terpyridyl)Ag2+ has been isolated as its peroxydisulphate salt.217 The presence of a d-+d band at 15600 cm-1 is indicative of a six-co-ordinate ion. X-ray photoelectron spectra have provided Ag(3d5/2>3/2) binding energies for this complex and the mono-terpy complex. The influence of pyridine and 2-, 3-, and 4-picoline on bis(diethyl dithio-carbamato)AgH has been examined by e.s.r. spectroscopy.218 The results indicate formation of mono-addition products and the spin hamiltonian parameters for these complexes have been determined. 

---