Mercury macrocyclic complexes: The synthesis of [Hg([18]aneN2S4)] and [Hg(Me2[18]aneN2S4)]. The single crystal x-ray structure of [Hg([18]aneN2S4)](PF6)2·4/3H2O

Reaction of HgSO₄ with one molar equivalent of L{L = 18]aneN₂S₄ (1,4,10,13-tetrathia-7,16-diazacyclooctadecane) or Me₂18]aneN₂S₄ (7,16-dimethyl-1,4,10,13-tetrathia-7,16-diazacyclooctadecane)} in refluxing MeOH-H₂O for 15 min affords a colourless solution containing the complex cation Hg(L)]²⁺. Addition of excess PF₆^? counterion gives the complex Hg(18]aneN₂S₄)](PF₆)₂·4/3H₂O as a cream coloured solid. A single crystal X-ray structure determination shows mercury(II) bound to a severely distorted octahedral arrangement of the six macrocyclic donor atoms, Hg---S = 2.655(5), 2.735(4), 2.751(4), 2.639(5) Å, Hg---N = 2.473(11), 2.472(17) Å. The cation is in a rac configuration with the two SCH₂CH₂NCH₂CH₂S linkages bound meridionally to the metal centre.