Structure Variation of Mercury(II) Halide Complexes with Different Imidazole-Containing Ligands

A series of coordination complexes with different structures [Hg(iimb)I2]·0.5acetone (1), [Hg(bib)Br2]·0.5THF (2),
[Hg(bib)I2] (3), [Hg3(tib)2I6]·2DMF (4), [Hg3(timpt)2I6]·4H2O (5), [Hg2(titmb)Br4] (6), and [Hg2(titmb)Cl4] (7) were synthesized by
reactions of mercury(II) halides with the corresponding imidazole-containing bidentate or tripodal ligands, namely, 1-(1-imidazolyl)-4-(imidazol-1-ylmethyl)benzene (iimb), 1-bromo-3,5-bis(imidazol-1-ylmethyl)benzene (bib), 1,3,5-tris(1-imidazolyl)benzene (tib),
2,4,6-tris[4-(imidazol-1-ylmethyl)phenyl]-1,3,5-triazine (timpt), and 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene (titmb),
respectively. The structures of the complexes were determined by single-crystal X-ray diffraction analyses, and the results revealed
that 1, 2, and 4−7 are one-dimensional (1D) chain coordination polymers with different shapes. In the case of 3, two metal atoms
and two bib ligands form M2L2 binuclear rings, which are further connected by weak Hg···I interactions to form an infinite 1D
chain. The different structures of the complexes showed the predominant influence of halides and organic ligands. In addition, the
weak interactions such as Hg−X···Hg (X = I or Br), I···I interactions also play an important role in the formation of supramolecular
architectures, for instance, to link low-dimensional entities to high-dimensional frameworks. Polycatenation of the 1D ladders was
observed in 1 to give a three-dimensional architecture. The photoluminescence properties of the synthesized mercury(II) complexes
were investigated in the solid state at room temperature.