Mn(II) and Co(II) mixed-ligand coordination compounds with acesulfame and 3-aminopyridine: synthesis and structural properties

Two mixed ligand complexes containing acesulfame (acs) and 3-aminopyridine (3-ap) ligands of Mn(II) and Co(II) were synthesized. The obtained compounds were characterized by various analysis methods. The geometries of complexes, C₁₈H₂₈MnN₆O₁₂S₂ (1) and C₁₈H₃₂CoN₆O₁₄S₂ (2), are distorted octahedra. Coordination of metal cations is provided by two molecules of 3-ap and four water ligands. In both structures, the 2+ charge of the metal required two monoanionic acs molecules located outside the coordination sphere. Complex 1 contains no hydrate water, while 2 contains two molecules of hydrate water. The crystal system of 1 is monoclinic and space group P2₁/c, while the crystal system of 2 is triclinic and space group P-1. Data on the removal of hydrate and crystalline waters in structures from thermal analysis curves support the described molecular structures. The bending vibrations of the bonds obtained from the FT-IR spectra match the crystal structure described. As a result of thermal analysis of both complexes, it was determined that the relevant metal cations remained in the reaction vessel as oxide (MnO and CoO) residues.