Syntheses, crystal structures, and photocatalytic properties of two zinc(II) coordination polymers based on dicarboxylates and flexible bis(benzimidazole) ligands

Two new ternary zinc(II) coordination polymers (CPs), catena-(μ2-phthalato)-(μ2-1,1′-hexane-1,6-diylbis(2-methyl-1H-benzimidazole))-zinc (CP 1) and catena-(μ2-phenylene-1,4-diacetato)-(μ2-1,1′-hexane-1,6-diylbis(1H-benzimidazole))-zinc (CP 2) were synthesized via hydrothermal process. CP 1 and CP 2 are named as [Zn(L1)(PA)]n and [Zn(L2)(PDA)]n (L1 = 1,1′-hexane-1,6-diylbis(2-methyl-1H-benzimidazole), L2 = 1,1′-hexane-1,6-diylbis(1H-benzimidazole), H2PA = phthalic acid, H2PDA = 1,4-phenylenediacetic acid)), respectively. Both CPs were characterized by elemental analysis, infrared spectroscopy, single crystal X-ray diffraction analysis. CP 1 possesses a 4-connected 66-dia network, CP 2 displays a 2D hcb layer with point symbol {63}. UV–Vis diffuse reflection spectra, luminescence and photocatalytic properties of two CPs for the degradation of the methylene blue (MB) dye were investigated. The mechanism of photocatalytic degradation of MB was also suggested.