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The gold(I) complex [Au(dppbO)Cl] was synthesized by reaction of Na[AuCl4]·2H2O with 1,2-bis(diphenylphosphino)benzene (dppb) in the presence of water. This is a new method for the synthesis of a bisphosphine monoxide gold(I) complex. The new gold(I) complex was characterized by NMR spectroscopy and X-ray crystal structure analysis. In the solid state structure a relatively short contact between the oxygen atom of the phosphine oxide group and the gold center was observed. The catalytic activity of [Au(dppbO)Cl] was tested for three different intermolecular alkyne hydrofunctionalization reactions. Silver tetrafluoroborate was used as co-catalyst for halide abstraction. While the bisphosphine monoxide gold(I) complex showed moderate activity for the hydration of various alkynes and the hydroamination of phenyl acetylene, high activity was observed for the hydroarylation of ethylpropiolate. Electron-rich arenes add very fast to the C-C triple bond but with relatively low selectivity.

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Abstract:In Zimapan, Mexico abundant mineral species have been identified. However, a significant number of these precious metals appear to be related to complex sulfides, as is the case of silver (Ag) in sulfosalts. In this work, a kinetic study of the formation of Ag complexes in the AgAsS 2 -S 2 O 3 2− -O 2 -NaOH system from a Zn concentrate found in the Zimapan mining district was conducted. The kinetic model application on Ag leaching shows a linear adjustment in the valuation of the particle size effect. The rate of formation of Ag complexes is dependent of temperature, leaching agent concentration and OH − concentration. Furthermore, graphical verification of the kinetic models indicates that the kinetics of the formation of Ag complexes correspond to the shrinking core model with chemical controls as the controlling stage. The formation of Ag complexes was confirmed by Fourier transform infrared (FTIR) spectroscopy.