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.

Two 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 as PowerPoint slide