Synthesis and structural elucidation of Co(II) and Mn(II) coordination polymers derived from isonicotinic acid

This study reports the solvothermal synthesis and characterisation of Co(II) and Mn(II) coordination polymers derived from isonicotinic acid (INA). Both complexes were obtained as crystalline solids and characterised using FT-IR spectroscopy, CHN elemental analysis, magnetic susceptibility measurements, powder X-ray diffraction (PXRD), and single-crystal unit cell determination for the cobalt complex. FT-IR spectra confirmed coordination through carboxylate oxygen and pyridine nitrogen atoms. Magnetic moment values of 4.53 BM (Co) and 5.81 BM (Mn) are consistent with high-spin configurations. Unit cell determination for the cobalt(II) compound indicated a monoclinic system with space group P2 1 , (a = 9.818 Å, b = 12.804 Å, c = 10.801 Å) consistent with a reported structure (CCDC 886304). PXRD analysis shows clear structural transformation from the free ligand, with good agreement between experimental and simulated patterns for the cobalt compound, confirming phase purity. The Mn(II) complex shows similar diffraction features, suggesting structural similarity. These results support the successful synthesis of coordination polymers with extended frameworks.