Bis(tetraphenylphosphonium) bis[N-(2,5-dichlorophenylsulfonyl)dithiocarbimato(2−)-κ2 S,S′]platinate(II)

In the title salt, (C24H20P)2[Pt(C7H3Cl2NO2S3)2], the PtII ion (site symmetry ) is coordinated by two S,S′-bidentate N-(2,5-dichlorophenylsulfonyl)dithiocarbimate ligands, resulting in a slightly distorted PtS4 square-planar geometry. In the crystal, a C—H⋯O interaction is observed, as well as electrostatic attraction between the oppositely charged ions.

In the title salt, (C 24 H 20 P) 2 [Pt(C 7 H 3 Cl 2 NO 2 S 3 ) 2 ], the Pt II ion (site symmetry 1) is coordinated by two S,S 0 -bidentate N-(2,5dichlorophenylsulfonyl)dithiocarbimate ligands, resulting in a slightly distorted PtS 4 square-planar geometry. In the crystal, a C-HÁ Á ÁO interaction is observed, as well as electrostatic attraction between the oppositely charged ions.

Experimental
Crystal data (C 24 H 20

Comment
We became interested in the syntheses and characterization of Pt(II) complexes with dithiocarbimates due to their potential application as antitumoral. Some platinum-dithiocarbimato-anionic complexes with general formulae [Pt(RSO 2 N═CS 2 )] 2-(R = aryl groups) have had their structures determined by X-ray diffraction techniques. All of these compounds have the tetrabutylammonium as counter-ion (Amim et al., 2008;Oliveira et al., 2004). Variations in the counter-ions and in the R group can be important to modulate the activity of these compounds favoring the biological application.
The title compound is quite stable at the ambient conditions. The Pt(II) is located at the inversion centre and the PtS 4 fragment has a distorted square-planar geometry due to the bidentate chelation ( Figure 1). The Pt-S bond lengths are almost equal but the angles S1-Pt-S2 and S2 i -Pt-S1 are 74.59 (2)° and 105.41 (2)° respectively (Table 1). In the fragment N═ CS 2 , the C-S bond lengths are nearly equal and are shorter than C-S single bonds (ca 1.815 Å) ( Allen et al., 1987). The C1═N bond distances [1.310 (3) Å] have a double character. This behavior indicates that the electron density is delocalized over the entire NCS 2 moiety. The S1-C1-N angle is significantly greater than S2-C1-N probably due to the repulsive interaction between the (2,5-Cl 2 C 2 H 3 )SO 2 group and the S1 atom, which are in cis position in relation to the C1-N bond.
The bond lengths and angles of the tetraphenylphosphonium cations are in agreement with the expected values (Allen et al., 1987). The crystal packing is mainly maintained by ionic bond, but there are weak interactions of the type C-H···O (Table 2).
The yellow solid obtained was filtered, washed with distilled water, ethyl alcohol and dried under reduced pressure. The title compound is slightly soluble in chloroform and insoluble in water and in most organic solvents. Yellow prisms of (I) were obtained after slow evaporation of solution of the compound in hot chloroform. M.p. 195.2-195.6°C. IR (most important bands, cm -1 ): 1409 ν(C═N); 1309 ν ass (SO 2 ); 1107 ν sym (SO 2 ); 932 ν ass (CS 2 ) and 312 ν(NiS).
supplementary materials sup-2 Refinement All H atoms were fixed geometrically and allowed to ride on their parent atoms, with C-H distances of 0.95 Å, and with U iso (H) = 1.2 U eq (C). Fig. 1. View of (I) with displacement ellipsoids drawn at the 30% probability level and H atoms omitted for clarity. (2)

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.