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

Abstract

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.