Anion and additive effects on the structure of Mercury(II) halides complexes with tripodal ligand

The metal complexes [Hg-2(tbim)(2)Br-4] center dot 2DMF (1) and [Hg-2(tbim)I-4] center dot 1.5DMF (2) were prepared by reactions of 1,3,5-tris(benzimidazol-l-ylmethyl)-2,4,6-trimethylbenzene (tbim) with HgBr2, HgI2, respectively, and [Hg-2(tbim)I-4] center dot 0.5(FeCp2) center dot H2O (3) was obtained by the same method with addition of ferrocene (FeCp2) as additive. Their structures were determined by X-ray crystallographic analyses. Complex 1 has a macrocyclic binuclear structure with one benzimidazole arm of the ligand free of coordination and the binuclear units are further connected by C-H center dot center dot center dot N hydrogen bonds to give an infinite zigzag chain. Complexes 2 and 3 have a 2D network structure in which tbim serves as a tridentate ligand. The results showed that the halides of bromide and iodide have remarkable impact on the structure of the complexes. The FeCp2 molecules are trapped in the voids of framework 3.