Syntheses, structures, luminescent and magnetic properties of a novel class of metal complexes constructed from 2-(2-pyridyl)benzimidazole and 5-hydroxy-1,3-benzenedicarboxylic acid

Four novel metal coordination polymers, [Zn(2-PBIM)(OH-BDC)]n (1), [Cd(2-PBIM)(OH-BDC)]n (2), [Mn(2-PBIM)(OH-BDC)]n·1.5nH2O (3), [Cu(2-PBIM)(OH-BDC)]n·nH2O (4) [2-PBIM = 2-(2-pyridyl)benzimidazole; OH-H2BDC = 5-hydroxy-1,3-benzenedicarboxylic acid], have been synthesized under hydrothermal conditions and structurally characterized by single crystal X-ray diffraction analysis, elemental analysis, IR spectroscopy, and thermogravimetric analysis. Compound 1 possesses left-handed screw (M-helix) and right-handed screw (P-helix) chains that are further connected though intermolecular hydrogen bonds and π–π stacking interactions resulting in a three-dimensional (3D) network. Compound 2 has a two-dimensional metal-organic framework which is connected into a 3D network by intermolecular hydrogen bonds and π–π stacking interactions. Compounds 3 and 4 are isostructural and possess one-dimensional (1D) channels. Free 2-PBIM and OH-H2BDC ligands and complexes 1, 2 show fluorescent emissions in the visible and near-infrared region. Magnetic susceptibility measurements indicate that both 3 and 4 exhibit antiferromagnetic coupling between adjacent center atoms.

Four novel metal coordination polymers have been synthesized under hydrothermal conditions and structurally characterized by single crystal X-ray diffraction analysis, elemental analysis, IR spectroscopy, and thermogravimetric analysis. Their fluorescent and magnetic properties have also been reported.Figure optionsDownload as PowerPoint slideHighlights
► Four novel metal coordination polymers have been synthesized and structurally characterized.
► Free ligands and complexes 1, 2 show fluorescent emissions in the visible and near-infrared region.
► Magnetic susceptibility measurements indicate that both 3 and 4 exhibit antiferromagnetic coupling.