Two cobalt complexes derived from 1H-1,2,3-triazole-4,5-dicarboxylic acid: Syntheses, structures and magnetic properties

• Two cobalt(II) complexes derived from azolate-carboxylic acid were synthesized and characterized.
• Dominant antiferromagnetic interactions between Co2 + ions in them were found.

Two cobalt(II) homometallic complexes, [Co2(HTDA)2(H2O)6·2H2O] (1) and {[Co3(TDA)2(H2O)8]·H2O}n(2) (H3TDA = 1H-1,2,3-triazole-4,5-dicarboxylic acid) have been synthesized and structurally characterized in detail. Single-crystal X-ray crystallographic study reveals that they crystallize in trigonal space group R-3 and orthorhombic space group Pna21, respectively. In 1, two Co2 + cations are bonded by two HTDA2 − ligands to generate a binuclear CoII unit, which can further be extended to a 3D supermolecular structure via the hydrogen bonds. At variance with 1, the nearest Co2 + cations of 2 are connected via TDA3 − ligands to form a 1D coordination polymer and can be further linked to each other to result in a 3D supermolecular framework through the hydrogen bonding interactions as well. The magnetic properties of them were studied in detail.

Two cobalt(II) homometallic complexes derived from 1H-1,2,3-triazole-4,5-dicarboxylic acid were synthesized and fully characterized. The magnetic properties were studied in detail to determine the following magnetic parameters: g = 2.47, D = 36.85 cm− 1, zJ = − 0.61 cm− 1, and R = 0.9979 for 1; A + B = 9.79 cm3 K mol− 1, E1 = − 31.27 K, E2 = − 1.55 K and R = 0.9998 for 2, respectively, suggesting dominant antiferromagnetic interaction between Co2 + ions.Figure optionsDownload as PowerPoint slide