Syntheses, crystal structures, and magnetic studies of two cobalt(II) coordination polymers based on concurrent ligand extension

•Two Co(II) coordination polymers with diverse structures have been synthesized and well characterized.•The structural distinction can be ascribed to the usage of different auxiliary ligand.•The magnetic investigation reveals a distinct occurrence of antiferromagnetic interactions in compounds 1 and 2.

An ether bridged tetracarboxylic acid ligand, 5-(3′,4′-Dicarboxylphenoxy)-isophthalic acid (H4L) was used to construct two Co(II) coordination polymers in presence of different nitrogen donor ligands such as 4,4′-bipyridine (4,4′-bpy) and 4,4′-bis(pyrid-4-yl)biphenyl (bpbp). The products formed under hydrothermal conditions are formulated as [Co2L(4,4′-bpy)2(H2O)3]n (1) and {[Co(bpbp)2(H2L)]·H2O}n (2). The compounds were characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis, and powder X-ray diffraction (PXRD) measurement. Compound 1 shows an intriguing (3,4,5)-connected 3D framework with a point symbol of (42 · 62 · 82)(42 · 65 · 83)(62 · 8). Compound 2 is an unusual 3D supramolecular framework generated by the one-dimensional [Co(bpbp)(H2L)]n polymer chain. The magnetic properties of compounds 1 and 2 were examined, indicating antiferromagnetic interactions between the cobalt(II) ions in the temperature range of 2–300 K.

Graphical abstractTwo new coordination polymers with ether bridged tetracarboxylic acid ligand 5-(3′,4′-Dicarboxylphenoxy)-isophthalic acid (H4L) and different nitrogen donor ligands, including 4,4′-bipyridine (4,4′-bpy) and 4,4′-bis(pyrid-4-yl)biphenyl (bpbp) have been hydrothermally synthesized and structurally characterized. Single-crystal X-ray diffraction analyses indicate that compound 1 is a 3D framework, whereas compound 2 shows a 3D supramolecular framework with 1D chain. The magnetic properties of complexes 1 and 2 were examined, indicating antiferromagnetic interactions between the cobalt(II) ions in the temperature range of 2–300 K.Under solvothermal condition, the reaction of Co(II) acetate with mixed-ligands 5-(3′,4′-Dicarboxylphenoxy)-isophthalic acid (H4L), 4,4′-bipyridine (4,4′-bpy) and 4,4′-bis(pyrid-4-yl)biphenyl (bpbp) affords two new coordination polymers.Figure optionsDownload full-size imageDownload as PowerPoint slide