On the selectivity of silver mediated thiolate transfer and the crystal structure of an unprecedented thiolate chloride Argentate(I) anion

Abstract

The reactivity of a series of fluorinated silver(I) thiolates (AgSRF) towards thiolation of dichloromethane by nucleophilic substitution in presence of bis(diphenylphosphane)methane (dppm) has been studied. Our results indicate that in the presence of an excess of CH2Cl2 the thiolate phosphine silver derivatives are capable of exchange thiolate and chloride to form, in different proportions, the correspondent chloromethylthioether (CH2Cl(SRF)) a or methyldithioether (CH2(SRF)2) b with the fluorinated SRF groups: SC6F4H 1, SC6H4(CF3)-2 2, SC6H3F2-3,4 3, SC6H3F2-2,4 4, SC6H3F2-3,5 5 and SC6H4F-2 6. Despite the kinetically preferred monosubstitution reaction, some of the thiolate derivatives tend to form selectively the disubstitution products, indicating a non-innocent role of the silver center in the formation of the product. Furthermore, we have isolated and structurally characterized, by X-ray diffraction, an ionic compound [Ag3(μ3-Cl)2(μ-Ph2PCH2PPh2)3][AgCl(SC6F4H)] that could be an intermediary product in the chloride-thiolate exchange reactions.