Structural diversity and fluorescence properties of three 2-sulfoterephthalate CdII/ZnII coordination polymers employing 1,4-bisbenzimidazole

• Three CdII/MnII 2-sulfoterephthalate complexes containing 1,4-bisbenzimidazole.
• Different structural features despite the same raw materials for 1 and 2.
• Fluorescence spectra exhibit the π–π* transition of organic ligands.

Three novel coordination polymers, namely, [Cd(2-Hstp)(1,4-bbi)(H2O)2]·3H2O (1), [Cd1.5(2-stp)(1,4-bbi)(H2O)2]·H2O (2) and [Zn2(2-stp)(μ2-OH)(1,4-bbi)1.5(H2O)]·6H2O (3) (2-H3stp is equal to 2-sulfoterephthalate and 1,4-bisbenzimidazole is equal to 1,4-bbi), have been synthesized by hydrothermal reaction. The structural analyses show that 1 and 2 possess different structural features despite the same raw materials, which are 1D chain structure featuring 6-member-water H-bonds cluster and 3D bbi-pillared wavy-like layer framework, respectively. As changing the metal ion to zinc ion, 3 exhibits 3D stp-pillared layer architecture, which discovers the effect of the central metal ions on the formation of metal–organic frameworks. The fluorescence studies show that the emissions of the coordination polymers are attributed to the ligand π–π* transition, which means they could be potential fluorescence materials.

Three new CdII/ZnII 2-sulfoterephthalate (2-H3stp) complexes with 1,4-bisbenzimidazole (1,4-bbi) are described. Complex 1 exhibits one-dimensional chain-like structure, 2 is a three-dimensional bbi-pillared wavy-like layer framework, while 3 is a three-dimensional stp-pillared layer architecture. Fluorescence spectra exhibit the π–π* transition of two organic ligands.Figure optionsDownload as PowerPoint slide