Mercury thioether chemistry: The synthesis and X-ray crystal structure of [Hg([15]aneS5](PF6)2

Reaction of mercury sulphate with one molar equivalent of [15]aneS5 (1,4,7,10,13-pentathiacyclopentadecane) in refluxing methanol/water for 2 h affords a colourless solution containing the complex cation [Hg([15]aneS5)]2+. Addition of excess NH4PF6 gives a white precipitate which can be recrystallized from acetonitrile/diethyl ether to give [Hg([15]aneS5)](PF6)2 as a white solid. An X-ray crystal structure determination shows the mercury (II) ion and one thioether sulphur-donor occupying a site of m symmetry with the macrocycle disordered over two equally likely conformations, neither of which possesses m symmetry, but which are mirror images of each other. The mercury (II) ion is bound to all five thioether donors of the macrocycle, giving a distorted square-based pyramidal stereochemistry, HgS = 2.491(6), 2.717(6), 2.561(8) A.