Infrared and Raman Studies of Mixed Cyanide-Halide Complexes of Trivalent Gold

Abstract

Crystalline dicyanide-dihalide complexes of gold(II1) (KXU(CX)~XZ, where X = C1, Br, or I) are formed on treatment of KAu( CN)Z with the free halogens coordinated halide in aqueous Au( CN)aXZ-is completely replaced by two equivalents of CN-; the reverse reaction does not occur in saturated halide solution. The highest cyanide complex of gold observed by means of infrared spectra in saturated KCN solution was AU(CN)~-. Chlorine treatment of K A u ( C N )~ and KBr in methanol yielded Khu(CN)3Cl. Oxidation of Ag(CN)S-with Brz does not yield a complex of Ag(II1) but AgBr and BrCN; iodine and chlorine react similarly. The infrared absorption spectra of Au( CN)zCl~-, Au( CN)zBrz-, Au( CN)zIz-, Au-(CN)aCl-, and HAu( CN)a,2HzO and the Raman spectra of Au( CN)zCI-and HAu( CN)4.2Hz0 were recorded. The spectrum of the solid acid, HAu(CN)4.2HzO, shows that the acidic hydrogen is hydrated to form H30+. The Raman and infrared spectra of Au(CN)3CI-suggest the planar configuration of CZ, symmetry.

Structural organization and dimensionality at the hands of weak intermolecular Au⋯Au, Au⋯X and X⋯X (X = Cl, Br, I) interactions

“…Slow evaporation of a methanol solution containing a nearly 1 : 4) alongside a yellow powder consisting of separately precipitated K[Au(CN) 2 ], K[AuBr 2 (CN) 2 ] and AuCN (as confirmed by IR 17,44,58 ). Crystals of 4 can also be obtained by slow evaporation of a stoichiometric solution, but in a much smaller yield.…”

“…This synthesis was based on a literature procedure. 44 Gaseous Cl 2 was bubbled through a 20 mL aqueous solution of K[Au(CN) 2 ] (1.071 g, 3.717 mmol) for ca. 5-10 min, resulting in a yellow tinted solution.…”

“…This synthesis was based on a literature procedure. 44 To a 10 mL methanol solution of K[Au(CN) 2 ] (106 mg, 0.367 mmol), a 20 mL ethanol solution of I 2 (97 mg, 0.382 mmol) was added, resulting in an intense red solution. This solution was stirred for two hours while covered with aluminum foil.…”

Photooxidation of Dicyanoaurate(I) Induced by Metal-to-Ligand Charge Transfer Excitation

“…At room temperature solutions of [Au(CN)2]-do not show any emission, and are not photoreactive in the absence of a suitable electron acceptor. How ever, in the presence of oxygen a photooxidation takes place which in the presence of chloride yields [Au(CN)2Cl2]~ as a well defined product [16].…”

Chemical Imaging of Monolayers on Metal Surfaces: Applications in Corrosion, Catalysis, and Self‐Assembled Monolayers

“…where peaks above 2200 cm −1 correspond to the [Au(CN) 4 ] − complex, which is the final corrosion product of the reaction 45. 46 Thus, by identifying the local vibrational spectra, the extent of corrosion at that locality can be determined.…”