Studying the impact of NCS- anion and the steric hindrance of flexible N-donor ligands on the crystal engineering of the mercury(II) coordination polymer

Two novel coordination polymers, [Hg(bib(Me))Cl-2](n) (1), [Hg-3(bib)(2)(NCS)(6)](n) (2), were prepared at room temperature by the reaction of appropriate salts of mercury(II) with 1,4-bis(2-methylimidazolyl)butane (bib(Me)) and 1,4-bis(imidazolyl) butane (bib) flexible linker ligands. The compounds were characterized by elemental analysis, IR spectroscopy, and single crystal X-ray diffraction. The mercury(II) ions adopt distorted tetrahedral geometry (HgNCl3) in 1, while trigonal bipyramidal coordination environment (HgN2S3) and octahedral arrangement (HgN4S2) in 2. In 1, one bib(Me) ligand is coordinated to one central Hg(II) to form a 3D framework with point symbol: 6(5).8. However, in 2, one or two bib ligands are coordinated to Hg(II) centers to form an open 3D framework with point symbol: 4(4).6(10).8.