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Reactions between methyldiphenylphosphane selenide, SePPh2Me, and different group 11 metal starting materials {CuCl, [CuNO3(PPh3)2], AgOTf, [AgOTf(PPh3)] (OTf = OSO2CF3), [AuCl(tht)], [Au(C6F5)(tht)] and [Au(C6F5)3(tht)] (tht = tetrahydrothiophene)} were performed in order to obtain several new species with metal–selenium bonds. The new complexes [CuCl(SePPh2Me)] (1), [AgOTf(SePPh2Me)] (2), [AuCl(SePPh2Me)] (5), [Au(C6F5)(SePPh2Me)] (6) and [Au(C6F5)3(SePPh2Me)] (7) were isolated and structurally characterized in solution by multinuclear NMR spectroscopy (1H, 31P, 77Se and 19F where appropriate). Solid products were isolated also from the reactions between SePPh2Me and [CuNO3(PPh3)2] or [AgOTf(PPh3)], respectively. NMR experiments, including low temperature 1H and 31P NMR, revealed for them a dynamic behaviour in solution, involving the transfer of selenium from PPh2Me to PPh3. In case of the isolated silver(i) containing solid an equilibrium between, respectively, monomeric [AgOTf(PPh3)(SePPh2Me)] (3) and [AgOTf(PPh2Me)(SePPh3)] (4), and dimeric [Ag(PPh3)(μ-SePPh2Me)]2(OTf)2(3a) and [Ag(PPh2Me)(μ-SePPh3)]2(OTf)2(4a) species was observed in solution. In case of the isolated copper(i) containing solid the NMR studies brought no clear evidence for a similar behaviour, but it can not be excluded in a first stage of the reaction. However the transfer of selenium between the two triorganophosphanes takes place also in this case, but the NMR spectra suggest that the final reaction mixture contains the free triorganophospane selenides SePPh2Me and SePPh3as well as the complex species [CuNO3(PPh3)2], [CuNO3(PPh2Me)2] and [CuNO3(PPh3)(PPh2Me)] in equilibrium. Single-crystal X-ray diffraction studies revealed monomeric structures for the gold(i) 6and gold(iii) 7complexes. In case of compound 6weak aurophilic gold(i)gold(i) contacts were also observed in the crystal. DFT calculations were performed in order to understand the solution behaviour of the silver(I) and copper(i) species containing both P(iii) and P(v) ligands, to verify the stability of possible dimeric species and to account for the aurophilic interactions found for 6. In addition, the nature of the electronic transitions involved in the absorption/emission processes observed for 6and 7in the solid state were also investigated by means of TD-DFT calculations. [ABSTRACT FROM AUTHOR]

The I2-adducts of drugs propylthiouracil (PTU) and methimazole (MeImSH) oxidize liquid mercury in dichloromethane to separate in good yield the neutral complexes [HgI2(PTU)2·MeOH] (1), [HgI2(PTU)2·HgI2] (2), and [Hg2I4(MeImSH)2] (3). The single crystal X-ray diffraction analysis of 1–2shows that the Hg(ii) center is coordinated by two sulfur atoms and by two iodine atoms in a tetrahedral geometry. In complex 2almost linear molecules of HgI2result encapsulated in the crystal packing enfolded by the hydrophobic propyl appendages of coordinated units of PTU. X-ray analysis of complex 3shows the presence of dimeric [Hg2I4(MeImSH)2] molecules to form Hg2S2I4cores. The intra- and intermolecular hydrogen bonds concerning PTU and MeImSH have been evaluated. The oxidation of Hg(0) to Hg(ii) requires a two-electron transfer process accomplished by an oxidative addition from the “activated” iodine moiety. The oxidizing and complexing properties of PTU-I2and MeImSH-I2have been interpreted considering the S-donor to I2interaction that leads to a charge separation between the sulfur-bound iodine atom S–I and the terminal I atom. Compounds 1, 2, and 3react with tetraethylammonium iodide to separate the compound (Et4N)2[HgI4] with the release of free PTU and MeImSH, respectively. The reported dissolution technique could be applied to the recovery of mercury from waste electrical and electronic equipment (WEEE) scrap, the nature of complexes 1–3makes it possible the easy separation of the mercury as tetraiodomercurate anion and the recycling of the donors. [ABSTRACT FROM AUTHOR]