Two 1-D metal-organic polymers constructed from bis-benzimidazole-based ligands: syntheses, crystal structures, and luminescent properties

By combination of Mn(II) and Hg(II) salts with a flexible building unit 1,1'-(1, 5-pentanediyl)bis-1H-benzimidazole (pbbm), two 1-D chain metal-organic polymers [Mn(SCN)2(pbbm)2]n (1) and {[HgCl2(pbbm)] DMF}n (2) have been prepared. The polymeric 1-D chains in 1 consist of parallel ribbons of rings, whereas 2 possesses a 1-D zig-zag chain framework based on tetrahedral mercury atoms bridged by pbbm molecules and terminally coordinated by two chlorides. The significant differences of these metal-organic frameworks indicate that the flexible pbbm ligand adjusts its conformation to meet the requirement of the coordination preference of the metal center. The photoluminescent properties of these new materials have been studied in the solid state at room temperature.