supplementary materials

The ability of tetrathiometallates to act as multidentate ligands has resulted in a rich coordination chemistry, which includes both discrete multimetal clusters such as [A(MS₄)₂]^2- (A = Fe, Co, Ni, Pd, Pt, Zn, Cd; M = Mo, W) and extended structures such as NH₄Cu[WS₄] (Müller et al., 1981). The compound reported here is the result of our ongoing research efforts on the synthesis of novel transition metal thiometallates.

The title compound, which was prepared under hydrothermal conditions, contains discrete WS₄^2- anions and tetraphenylphosphonium [Ph₄P]⁺ cations. The local coordination and the atom-labelling scheme are shown in Figure 1. Each tungsten atom is surrounded by four sulfur atoms in a tetrahedral coordination. The S—W—S bond angles range from 108.59 (4) to 110.82 (7) whilst the four W—S distances are nearly identical ranging from 2.1915 (9) to 2.1962 (10) Å, and are similar to those found in [NH₄]₂[WS₄] (Sasvári, 1963).

The [Ph₄P]⁺ cations are arranged into zigzag chains (Figure 2) in which each phenyl group points towards another phenyl group in a neighbouring cation, with the H atoms of a given ring oriented towards the π electron density of the second phenyl ring. It has been proposed that attractive interactions between the phenyl groups of [Ph₄P]⁺cations play a major role in the crystal packing of compounds of this type (Dance & Scudder, 1995). In particular, the so-called sextuple phenyl embrace, in which three phenyl groups of a [Ph₄P]⁺ cation face three phenyl groups of an adjacent [Ph₄P]⁺ cation in an edge-to-face conformation, is a frequently observed supramolecular motif (Dance & Scudder, 1996). As illustrated by Figure 2, the zigzag chains of [Ph₄P]⁺cations found in the title compound could be described by considering each [Ph₄P]⁺cation to interact with its two neighbours through sextuple phenyl embraces. The P···P distances within the chain are ca 6.5 Å, comparable to those observed in compounds containing this type of chain (Dance & Scudder, 1996). The structure of the title compound contains zigzag [Ph₄P]⁺ chains running along the [110] and [110] directions (Figure 3). There are relatively short P···P distances, of ca 7.3 Å, between [Ph₄P]⁺cations from different chains, which involve two face-to-face phenyl interactions, suggesting that there may be additional interchain supramolecular interactions. This type of interaction has been reported previously (Dance & Scudder,1996), and has been termed quadruple phenyl embrace. The tetrathiotungstate anions are located in the cavities created between the cation chains (Figure 3). A number [Ph₄P]⁺ salts, containing chemically diverse tetrahedral anions, adopt a similar crystal structure. Isostructural compounds that have been reported include selenometallates such as [Ph₄P]₂[MoSe₄] (O'Neal & Kolis, 1988) and [Ph₄P]₂[WSe₄] (O'Neal & Kolis, 1988), and halometalates like [Ph₄P]₂[NiCl₄] (Ruhlandt-Senge & Müller, 1990), [Ph₄P]₂[CdBr₄] and [Ph₄P]₂[HgBr₄] (Hasselgren et al., 1997).