Poly[(μ3-4-aminobenzenesulfonato-κ3 N:O:O)(triphenylphosphine-κP)silver(I)]

In the title 1:1 silver 4-aminobenzenesulfonate adduct with triphenylphosphine, [Ag(C6H6NO3S)(C18H15P)]n, the sulfonate –SO3 unit bridges, through only one O atom, two phosphine-coordinated Ag atoms, forming a centrosymmetric Ag2O2 rhombus. The Ag+ cation adopts a considerably distorted a tetrahedral coordination. In the crystal, adjacent binuclear molecules are connected into a layer motif through the amino group of the anion; the layers are perpendicular to the a axis.

In the title 1:1 silver 4-aminobenzenesulfonate adduct with triphenylphosphine, [Ag(C 6 H 6 NO 3 S)(C 18 H 15 P)] n , the sulfonate -SO 3 unit bridges, through only one O atom, two phosphine-coordinated Ag atoms, forming a centrosymmetric Ag 2 O 2 rhombus. The Ag + cation adopts a considerably distorted a tetrahedral coordination. In the crystal, adjacent binuclear molecules are connected into a layer motif through the amino group of the anion; the layers are perpendicular to the a axis.

Comment
The crystal structure of silver 4-aminobenzenesulfonate, sulfargenta, a chemical whose ability to disinfect contaminated water was reported in 1945 (Léon, 1945;1992), features a polymeric ribbon structure in which the nitrogen and three oxygen atoms are all involved in coordinating to silver centers (Schreuer, 1999;Pan et al., 2003). The 4-aminobenzenesulfonate ion has been studied in other metal salts; the sulfonate part of the ion exhibits diverse coordination modes, as summarized in a review of metal arenesulfonates (Cai, 2004).
Introducing a monodentate ligand such as triphenylphosphine to silver 4-aminobenzenesulfonate should lower the dimensionality (i.e., the adduct should exist as a monomeric molecule) following the suggestion of lowering the dimensionality of the related metal carboxylates by the use of bidentate N-heterocycles. However, the hexamethyleneteramine adduct has a layer structure in which only the hexamethylenetetramine ligand participates in µ 3 -bridging (Zheng et al., 2002); the 1,1'-(1,4-butanediyl)-bis(imidazole) adduct similarly features an uncoordinated 4-aminobenzesulfonate group (Li et al., 2006). Other bidentate N-heterocycles result in silver 4-aminobenzenesulfonate adducts displaying chain or ladder motifs Liu, Wy et al., 2007;Wu et al., 2008). In the present study, the donor ligand is triphenylphosphine.
In the title 1:1 adduct with triphenylphosphine the sulfonate -SO 3 group bridges, through only one oxygen atom, two phosphine-coordinated silver atoms to furnish a centrosymmetric Ag 2 O 2 rhombus (Fig. 1). The silver atom has a tetrahedral geometry as seen from the selected bond distances and angles involving atom Ag1, given in Table 1. In the -SO 3 portion, one bond is distinctly longer than the other two [1.489 (2) Å compared to 1.444 (2) and 1.457 (2) Å]; the oxygen atom involved in the longer bond is that which bridges the two silver atoms. Sulfanilic acid itself exists as a zwitterion but the longest bond is only slightly longer than the other two [1.476 (1) Å compared to 1.445 (1), and 1.457 (1) Å] (Low & Glidewell, 2002). On the other hand, the bonds are more symmetrical in the two modifications of the monohydrated acid (Banu et al., 2006;Rae & Maslen, 1962).
In the crystal structures of metal 4-aminobenzesulfonates (without other ligands) for which the anion is coordinated to the metal, the amino group is not usually involved in additional coordination. The exceptions are limited to silver (Schreuer, 1999;Pan et al., 2003) and mercury (Brodersen & Beck, 2004) derivatives only. In the crystal structute of the title compound adjacent [Ag(C 6 H 6 NO 3 S)(C 18 H 15 P)] 2 dimers are connected into a layer motif through the amino moiety. The layers are perpendicular to the a-axis of the monoclinic unit cell (Fig. 2), with the aromatic rings of the phosphine ligand protruding into the space between the layers.

Refinement
Hydrogen atoms were placed in calculated positions and treated as riding atoms: C-H 0.95, N-H 0.86 Å with U iso (H) = 1.2U eq (parent c-or N-atom). Fig. 1. Thermal ellipsoid plot (Barbour, 2001) of a portion of the asymmetric unit of the twodimensional network structure of the title compound; ellipsoids are drawn at the 70% probability level and H atoms are of arbitrary radius. Symmetry transformation: (i) = 1 -x, 1 -y, 1z; (ii) = 3/2 -x, y -1/2, 3/2 -z. (Dolomanov et al., 2003) representation of the layer motif in the crystal structure of the title compound.