Gold-197 Moessbauer studies of some gold(I) thiolates and their phosphine complexes including certain antiarthritic gold drugs

Abstract

identified (IR spectrum, melting point) as the original Co cluster catalyst. An immobile green material, which was not identified, always was present on top of the silicic acid pad.Table I summarizes the experimental details of the catalysis experiments.Infrared Studies of Hydroformylation Reaction Mixtures. In these experiments, the cooled and depressurized reactor was opened to a nitrogen atmosphere in the drybox, and a sample of the reaction mixture was placed in a 0.1-mm path length NaCl solution cell and sealed from the atmosphere. An IR spectrum was recorded of the v(CmO) region (2150-1800 cm"1) with a Perkin-Elmer 180 grating infrared spectrophotometer using toluene as the reference solvent. IR spectra also were recorded for pure PhCCo3(CO)9 and Co2(CO)8.Table II summarizes these IR data.

Injectable and Self-Healing Dynamic Hydrogels Based on Metal(I)-Thiolate/Disulfide Exchange as Biomaterials with Tunable Mechanical Properties

“…For comparison, Au60 was prepared by using an aqueous solution of Au(I) ions prepared as previously described. 33 The liquid-to-gel transition was observed at the exact same frequency for Au60 and Ag60 (as shown in Figure 8B). Identical λ t confirms that not only [S − ] but also [SS] affect the rate of the exchange reaction responsible for the dynamic properties of the hydrogel.…”

“…37−40 Obviously, the final material will contain a mixture of Au−S species (which are expected to self-assemble via Au(I)−Au(I) aurophilic attractions) and disulfide bonds at acidic pH ( Figure 1A). 33,41 Quantification of the amount of free thiols for (PEGSH) 4 was carried out by Ellman's test and was found to be around 0.24 μmol SH/mg of polymer. This value was much lower than the theoretical amount of free thiols calculated at 0.4 μmol SH/ mg, assuming that all end chains of (PEGSH) 4 are functionalized with a thiol group.…”

“…Despite the efficient protection of thiolates by Au(I), one major drawback of this system was the inherent difficulty to prepare aqueous solutions of Au(I) ions, which are likely unstable at room temperature. 33 Also, free-standing hydrogels at physiological pH could not be achieved due to the permanent exchange. This flowing behavior under gravity could represent a major issue for tissue engineering applications, where the hydrogel scaffold must remain at the same location, or for tissues exhibiting high stiffness, e.g., NP and cartilage.…”

Speciation analysis of the antirheumatic agent Auranofin and its thiol adducts by LC/ESI-MS and LC/ICP-MS

“…It has been reported in the literature that Auranofin exists as a monomeric species in the solid state as well as in various solvents (deuterated dimethyl sulfoxide, acetone, methanol, chloroform and water). 5,8 In this study, Auranofin analysis was performed in a buffered solution of ammonium bicarbonate at pH 7.4, the physiological pH of blood. In the positive ion mode, three major species could be identified: The displacement of the phosphine ligand and formation of such clusters is remarkable.…”

Applications of NMR spectroscopy in understanding the gold biochemistry

“…The crystal structure of auranofin shows that gold is linearly coordinated by the sulfur atom of thioglucose and the phosphorus of Et 3 P to give a discrete monomeric molecular species [11]. Gold thiolates are polymeric in nature [12][13][14] (by sulfur bridging) with a gold-gold interaction (Fig. 2).…”