[Hg2]2+ coordinated by eight nitrogen donor atoms: Synthesis and structure of [Hg2(phen)4](OTf)2, phen = 1,10-phenanthroline

The mercury(I) complexes [Hg2(phen)4](OTf)2 and [Hg2(phen)2](OTf)2 (phen = 1,10-phenanthroline) were prepared and characterized by single crystal X-ray diffraction. The structure of [Hg2(phen)4](OTf)2 exhibits an Hg2N8 kernel, which involves the highest number of N-donor atoms coordinated to Hg 2 2 + reported so far. The Hg–N distances of [Hg2(phen)4](OTf)2 cover a range of 238.5–266.6 pm. Supramolecular structures were built in both complexes via π–π stacking of the phenanthroline ligands.