Supramolecular aggregation patterns in the crystal structures of the dinuclear phosphinegold(i) thiolates, [(Ph2P(CH2)4PPh2){AuSC(OR)NC6H4Y-4}2] for R = Me, Et or iPr and Y = H, NO2 or Me: the influence on intermolecular interactions exerted by R and Y

Abstract

The molecular structures of all but the R = Et/Y = NO₂ derivative of the series of structures [(Ph₂P(CH₂)₄PPh₂){AuSC(OR)NC₆H₄Y-4}₂] for R = Me, Et or iPr and Y = H, NO₂ or Me, display anti-conformations with the carbonimidothioate ligands external to the dppb (Ph₂P(CH₂)₄PPh₂) bridge. In the exceptional structure, the thiolate ligands occupy positions proximate to the dppb bridge, an observation rationalized in terms of the dictates of crystal packing. Aurophilic (Au⋯Au) interactions are not observed in their molecular or in their crystal structures. In the Y = NO₂ structures, C–H⋯O interactions dominate the crystal packing leading to chain (R = Me or iPr) and layer (R = Et) motifs. Synthons of the type {Au⋯S}₂ dominate the crystal packing, leading to a chain, in one example, i.e. R = Me and Y = H. Similar {Au⋯S}₂ synthons potentially appear in all the remaining structures except for R = Et and Y = H, but the Au⋯S distances are too long to be considered significant so that C–H⋯S interactions clearly dominate the crystal packing. With the exception of the layer motif found for the R = Et and Y = NO₂ derivative, chain motifs, mediated by {Au⋯S}₂, C–H⋯O or C–H⋯S interactions persist in the crystal structures.