Two Cadmium(II) Coordination Polymers from Flexible Bis(imidazolyl) Ligands

The hydrothermal reaction of 1,4-bis(imidazol-1'-yl)butane (bimb) and 1,4-bis(2-methylimidazol-1'-yl)butane (bmib) with CdBr2 center dot 4H(2)O gave rise to two coordination polymers, [Cd(bimb)(2)Br-2](n) (1) and [Cd(bmib)Br-2](n) (2), respectively. Single-crystal X-ray diffraction analysis reveals that 1 and 2 crystallize in the monoclinic space group P2(1)/n and the orthorhombic space group Peen, respectively. In 1, bimb adopts an anti-anti-anti conformation and bridges adjacent Cd(II) to form a two-dimensional (2D) network containing rhombohedral rings. The 2D layers are arranged in an offset ABCABC sequence to fill large void in the rhombohedral rings. In 2, bmib also exhibits an anti-anti-anti conformation, but it links neighboring Cd(II) into a one-dimensional (1D) chain. Br- in 1 and 2 serves as a monodentate ligand to balance charge.