The crystal structure of (Ph4P)2[Hg2(SPh)6]: Synthesis, characterization and structure supramolecularity

Abstract

X-ray analysis at ambient temperature has established the crystal structure of the monoclinic (Ph4P)2[Hg2(SPh)6]. It contains the bitetrahedral [(PhS)2Hg(μ-SPh)2Hg(SPh)2]2− anionic complex, in contrast to most mercury thiolate complexes, which contain the distorted-trigonal [Hg(SPh)3]− species. The crystal supramolecularity was analysed in the context of the issue of Ph ··· Ph (phenyl ··· phenyl) supramolecular synthons and the relative energies of intraionic and interionic interactions. The crystal lattice is dominated by the Ph ··· Ph supramolecular synthons, containing parallel chains of Ph4P+ ions and stacks of [Hg2(SPh)6]2− ions. Each chain of cations contains alternating 6PE (sixfold phenyl embrace) and P4PE (parallel fourfold phenyl embrace) motifs, with a repeat distance. The canting of [Hg2(SPh)6]2− ions relative to their stack axis is correlated with the repeat length of the cation chains, with EF (edge-to-face) and OFF (offset-face-to-face) Ph ··· Ph interactions between Ph4P+ and [Hg2(SPh)6]2−. The strength and directionality of these supramolecular synthons are evident in the calculated through-space energies (−16.7 kJ mol−1 per two Ph4P+ ions engaged in a P4PE and −42.3 kJ mol−1 per two Ph4P+ ions engaged in a 6PE).