Gold halide complexes

For example, AuCl immediately decomposes into gold and gold(III) chloride, though some gold(I) halide complexes such as Aul2 are quite stable, while Au(CN)2 is formed by oxidation of gold in the presence of CN ... 

Schwerdtfeger, P. (1989) Relativistic effects in gold chemistry. II. The stability of complex halides of Au(III). Journal of the American Chemical Society, 111, 7261-7262. 

Mossbauer studies on gold compounds were first reported by Roberts et al. [337] and Shirley et al. [338, 339]. They observed rather large isomer shift changes in some simple gold (I) and gold (III) halides and in halogeno-complexes such as AuX (X = Cl, Br, I), AuXj (X = F, Cl), K[AuX4] (X = F, Cl, Br), and... 

Another particularly convenient preparative method is the reaction of the corresponding gold(l) acetylacetonate complex with the alkyne, which requires no auxiliary base.42 68-71 This reaction is also useful for the simple acetylides (L)AuC=CH.72 The acetylacetonates can be isolated and introduced as the true reagents, or prepared in situ using the corresponding gold(l) halide complex and Tl(acac) (Equations (16) and (17)).73... 

In general, gold cations Au+ and their adducts with auxiliary ligands [LAu]+, as well as gold(i) halides AuX, form only weak 7r-complexes with alkynes. Stable compounds have been isolated only with special combinations of components, but unstable species may nevertheless play an important role in gold chemistry as short-lived intermediates or transient species. 

Kneen has also prepared a large number of gold complexes. He has found that the ligands considered in this review form two types of complex with gold(I) halides ... 

Figure 2.46 Different geometries in gold complexes with bidentate diphosphines and halide ligands.

Since the metal center in gold complexes usually displays acid character, Au- -NM contacts will be more easily formed as the basicity of the non-metal increases. Thus, there are many gold- -halogen weak interactions between cationic gold complexes and halides or anions of which the halogen forms part, but most are individual contacts between ions that do not generate supramolecular structures. For example, about 50% of Au- -Cl contacts are isolated cation- -anion interactions. 

In the same manner, a number of alkyl (43), vinyl (69, 203), aryl (204), and cyclopentadienyl (98, 100-102) complexes of gold(I) are cleaved by halogens to yield the corresponding gold(I) halides and the halo-substituted organic species. 

Cyclohexyldienyl complexes, with Ti(IV), 4, 327 Cyclohexylisocyanides, with gold(I) halides, 2, 281 Cyclohexylphosphine, for semiconductor growth, 12, 9 Cyclohexyl selenides, preparation, 9, 480 Cyclohydrocarbonylation alkenes, 11, 515 alkynes, 11, 522 dienes, 11, 522 overview, 11, 511-555 for ring expansion, 11, 527 Cycloisomerizations, via silver catalysts, 9, 558 Cyclomanganation, product types, 5, 777-778 Cyclometallated azobenzenes, liquid crystals, 12, 251 Cyclometallated complexes for OLEDs... 

Other active methylene compounds also react with both palladium(ll) <2002POL2653> and gold(m) <1997JOM243> to produce metallacyclobutane complexes (Scheme 34). The gold complex is not sufficiently stable for isolation. In these reactions, the silver oxide functions both as a base and a reagent for halide abstraction. In the gold series, 1,1,3,3-tetracyanopropane is also a competent pro-nucleophile <1999JOM219>. 

Fig. 5. Experimental s-i(s) values (crosses) for gold(III) halide solutions compared with theoretical values (solid lines) calculated for square-planar AuX4 complexes.

Fig. 6. Radial distribution functions, D(r), for the gold(III) halide solutions (solid lines), compared with calculated peaks (dots) for a square-planar AuX,t complex. The 47rr2p0 functions are shown by dotted lines. 

The PtCl42- and PdCl42 complexes have the same square-planar structure as the gold(III) halide complexes and concentrated solutions of each of them can be prepared. In crystal structures the Pt—Cl and the Pd—Cl bond lengths in these complexes do not differ significantly and their solution diffraction curves show this to be true also in solution. They can, therefore, be expected to form isostructural solutions and the difference between the normalized diffraction curves for a platinate(II)... 

Like trialkylgold compounds (R3AU), monoaUcylgold compounds (RAu) are unstable in the absence of a donor ligand L. Their preparation is therefore carried out by treatment of a suitable complex of a gold(I) halide (L-AuX) with the organolithium reagent. Arylation follows the same pathway (equations 4 and 5). 

From carbodiphosphoranes R3P=C=PR3 and dialkyl-gold(III) halides, cyclic ylide complexes containing four Au-C <7-bonds are obtained in a multiple transylidation reaction (equation 24). Related thiophosphorus ylides and sulfonium and sulfoxonium ylides are equally effective in the formation of Au-C <7-bonds, and a series of analogous gold thiophosphonium and sulfoxonium-methyhde complexes is available (equations 25-27). ... 

Ammonia complexes.. EflFect of complex formation on solubility. Cyanide complexes. The cyanide process of treating gold and silver ores. Complex halides and other complexes. Sodium thiosulfate as photographic fixer. Hydroxide complexes. Amphoteric hydroxides. Sulfide complexes. Equilibrium expressions for complex formation. Structural chemistry—tetrahedral, octahedral, square complexes. Existence of isomers. 

The pure and stable organogold (I) compounds, RAuL, can be prepared starting from a gold(I) halide-ligand complex ... 

---