Polysulfonylamines. CLXXXIV. Crystal Structures of Molecular Triphenylphosphanegold(I) Di(4-X-benzenesulfonyl)amides: Isomorphism and Close Packing (X = Me, F, Cl, NO2) vs. Structure-Determining C-X···Au/O Halogen Bonds (X = Br, I)

摘要

In order to study the structure-determining influence that halogen bonding can exert during the course of crystallization, solid-state structures are compared for two previously reported and four new molecular gold(I) complexes of the type Ph3P-Au-N(SO2-C6H4-4-X)(2), each featuring linear P,N coordination at gold and two phenyl rings with varying p-substituents X = Me, F, Cl, NO2, Br or I. The compounds were synthesized by reactions of Ph3PAuX (X = Cl or 1) with the corresponding silver di(arenesulfonyl)amides, crystallized from dichloromethane, and characterized by low-temperature X-ray diffraction. The Me, F, Cl and NO2 congeners are isomorphic and crystallize without solvent inclusion in the chiral orthorhombic space group P2(1)2(1)2(1) (Z' = 1). These structures are governed by isotropic close packing via three-dimensional 21 symmetry, incidentally supported by an invariant set of C-H center dot O=S hydrogen bonds, CH/pi interactions and pi/pi stackings of aromatic rings; in particular, the hard halogen atoms of the fluoro and the chloro homologues are not involved in X center dot center dot center dot Au, X center dot center dot center dot O or X center dot center dot center dot X interactions. The higher homologues, with soft halogen atoms, were obtained as a dichloromethane hemisolvate for X = Br and a corresponding monosolvate for X = I, each triclinic in the centrosymmetric space group P1 (Z' = 1). Here, the primary structural effect is implemented by infinite chains in which translation-related molecules are connected for the bromo compound by a bifurcated Au center dot center dot center dot Br(2)center dot center dot center dot O=S interaction, for the iodo congener by an equivalent Au center dot center dot center dot I(2)center dot center dot center dot O=S interaction and a short halogen bond C-I(1)center dot center dot center dot O=S. The latter bond is stronger than a similar C-Br center dot center dot center dot O=S interaction and induces a conformational adjustment of the (CSO2)(2)N group from the normal twofold symmetry in the bromo compound to an energetically unfavourable asymmetric form in the iodo homologue. In both cases, pairs of antiparallel molecular catemers are associated into strands via sixfold phenyl embraces, the strands are stacked to form layers, the solvent molecules are intercalated between adjacent layers, and the crystal packings are reinforced by a number of C-H center dot center dot center dot O=S hydrogen bonds and interactions of aromatic rings.