A simple competition assay to probe pentacopper(I)-thiolato cluster ligand exchange.

Two pentanuclear copper(I) thiolato clusters of the formula [Cu(5)(L)(3)](-) (L = pyridine-2,6-dimethanethiolate (L1), (1); 4-methylpyridine-2,6-dimethanethiolate (L2), (2)) were synthesized utilizing a single-step procedure, and their structures were characterized by X-ray crystallography. The aforementioned pentanuclear complexes possess an interesting propeller-like Cu(5)S(6) core where all Cu centers are three-coordinate. Electrospray ionization mass spectrometry (ESI-MS) investigation of the pentanuclear copper(I) thiolato clusters with added hetero-ligands demonstrated interesting ligand exchange behavior. The product distribution resulting from ligand exchange not only depended on the quantity of added ligand, but also was sensitive to the coordination ability of the ligand. The ESI-MS method used in this study can serve as a useful tool for probing exchange behavior in coordination metal complexes that cannot otherwise be determined by NMR.

Potassium-encapsulated arsenic-dithiolato compounds: synthesis, structural calculation, and biological relevance.

This study based on the synthesis, characterization, and structural calculation of small molecular potassium-encapsulated arsenic-dithiolato compounds will provide fundamental knowledge about arsenic metabolism behavior in biological system. Two novel air-stable potassium-encapsulated arsenic-dithiolato compounds, [K@As(2)(L1)(3)](BF(4)) (1) and [K@As(2)(L2)(3)](BF(4)) (2), were prepared using deprotonated 2,6-bis(mercaptomethyl)pyridine (L1H(2)) and 1,3-dimercapto-m-xylene (L2H(2)) to react with AsCl(3) in the presence of potassium cation. Compounds 1 and 2 have been characterized by electrospray ionization-mass spectra, nuclear magnetic resonance spectra, and elemental microanalysis. Density functional theory calculation also supports the formation and binding properties of the potassium-encapsulated arsenic-dithiolato compounds.