Bis(tetraphenylphosphonium) bis[N-(trifluoromethylsulfonyl)dithiocarbimato(2−)-κ2 S,S′]zincate(II)

The title salt, (C24H20P)2[Zn(C2F3NO2S3)2], consists of a complex dianion and two tetraphenylphosphonium cations. The ZnII ion displays a distorted tetrahedral coordination environment with four S atoms from two S,S′-chelated N-(trifluoromethylsulfonyl)dithiocarbimate anions. In the crystal, besides the ionic interaction of the oppositely charged ions, intermolecular C—H⋯O interactions between cations and anions are observed. One of the cations interacts with an inversion-related equivalent by π–π stacking between phenyl rings, with a centroid–centroid distance of 3.932 (4) Å.

The title salt, (C 24 H 20 P) 2 [Zn(C 2 F 3 NO 2 S 3 ) 2 ], consists of a complex dianion and two tetraphenylphosphonium cations. The Zn II ion displays a distorted tetrahedral coordination environment with four S atoms from two S,S 0 -chelated N-(trifluoromethylsulfonyl)dithiocarbimate anions. In the crystal, besides the ionic interaction of the oppositely charged ions, intermolecular C-HÁ Á ÁO interactions between cations and anions are observed. One of the cations interacts with an inversion-related equivalent bystacking between phenyl rings, with a centroid-centroid distance of 3.932 (4) Å .

Comment
We became interested in the syntheses and characterization of dithiocarbimato-metal complexes due to their similarities with dithiocarbamato complexes, which are important fungicides (Hogarth, 2005). While the dithiocarbamato-metal(II) are neutral substances, the analogous dithiocarbimato-complexes are necessarily anionic species. Thus, the choice of metallic ion, active counter ions or the use of different R groups on the dithiocarbimate structures could improve and/or modulate the antifungal activity.
The title complex is a new member of the class of Zn complexes with general formula [Zn(RSO 2 N═CS 2 ) 2 ] 2- (Amim et al., 2011;Alves et al., 2009;Mariano et al., 2007;Perpétuo et al., 2003). The literature describes only one complex of this class having an alkyl group (methyl) attached to the SO 2 moiety (Oliveira et al., 2007). The asymmetric unit of the title compound is shown in Fig. 1, and consists of one [Zn(CF 3 SO 2 N═CS 2 ) 2 ] 2anion and two Ph 4 P + cations. The Zn II ion is coordinated by two S,S'-chelated N-trifluoromethylsulfonyldithiocarbimate ligands, resulting in a slightly distorted ZnS 4 tetrahedral geometry. Due to the formation of the two ZnS 2 C four membered rings, the two S-Zn-S angles containing both sulfur atoms of the same ligand are significantly smaller than those containing the sulfur atoms from two ligands (Table 1). The dihedral angle between the two ZnS 2 C four membered rings [87.40 (4)°] is greater than that found in the salt (Ph 4 P) 2 [Zn(CH 3 SO 2 N═CS 2 ) 2 ] of 79.1 (1)° (Oliveira et al., 2007). The C-S [average value of 1.731 Å] and C═N bond distances [1.315 (4) and 1.314 (4) Å] have double bond character. This behavior indicates that the electron density is delocalized over the entire NCS 2 moiety. The S1-C1-N1 and S5-C3-N2 angles are significantly greater than S2-C1-N1 and S4-C3-N2 due to the repulsive interactions between the two SO 2 CF 3 groups and the S1 and S5 atoms, respectively, which are cis in relation to the C1-N1 and C3-N2 bonds. Similar behavior is observed for other zinc complexes with dithiocarbimato ligands (Amim et al., 2011;Alves et al., 2009;Oliveira et al., 2007;Perpétuo et al., 2003). The torsion angles of C1-N1-S3-C2 and C3-N2-S6-C4 describing the conformation of the dithiocarbimato ligands are -175.9 (3)°a nd 180.0 (3)°, respectively. These angles are -67.1 (2)° and 159.6 (2)° in the compound (Ph 4 P) 2 [Zn(CH 3 SO 2 N═CS 2 ) 2 ] (Oliveira et al., 2007), probably due to the larger size of the CF 3 group and the intermolecular interaction present in the title compound.
In both tetraphenylphosphonium cations, the P-C bond lengths range from 1.785 (3) to 1.803 (3) Å, the C-P-C angles range from 106.6 (2) to 112.1 (1)°, and the P atoms display slightly distorted tetrahedral geometry. The arrangement of molecules is mainly determined by the electrostatic interactions between oppositely charged units. Moreover, there are intermolecular C-H···O interactions between cations and anions ( Table 2) and π-π stacking between phenyl rings on inversion related (1-x, -y, 2-z) cations.

supplementary materials sup-2 Experimental
The potassium trifluoromethylsulfonyldithiocarbimate dihydrate was prepared in dimethylformamide from trifluoromethanesulfonamide as described in the literature (Franca et al., 2006). The title compound was prepared in 1:1 (10 ml) methanol:water by the reaction of zinc acetate dihydrate (1.0 mmol) with trifluoromethylsulfonyldithiocarbimate dihydrate (2.0 mmol) and tetraphenylphosphanium chloride (2.0 mmol). The reaction mixture was stirred for 1 h at room temperature.
The white solid obtained was filtered, washed with distilled water and dried under reduced pressure. The title compound is insoluble in water but soluble in chloroform, methanol and dichloromethane. Suitable crystals were obtained after slow

Refinement
H atoms were geometrically positioned (C-H 0.93 Å) and refined as riding, with U iso (H) = 1.2 U eq of the parent atom. Anisotropic displacement parameters were made equal for the S3, O2 and O1 atoms, using the SHELXL-97 EADP constraint.
Reflections (-1 1 2) and (0 4 2) were omitted because they were partially obscured by the beamstop. Fig. 1. Representation of the title compound, with displacement ellipsoids drawn at the 30% probability level.