Novel metal chelates with thiourea and nicotinic acid: Synthesis, structural characterization, and biological properties

The interaction of nicotinic acid and thiourea with the chloride salts of Ca(II), Mg(II), Co(II), Ni(II), Cu(II), and Fe(III) ions led to the synthesis of a unique series of metal chelates. All formed metal complexes were clarified using a variety of analytical and spectral techniques, besides magnetic moment and thermal tests. The electronic and magnetic measurements indicated that the paramagnetic chelates (3) and (4), as well as the diamagnetic complexes (1) and (2), were responsible for the tetrahedral geometrical structure. The outcomes also led to the production of square-planar, and high-spin octahedral structures for chelates (5) and (6). Thermodynamic studies using activation energy values revealed that complex (1) is more thermally stable than complex (2) and complex (3) is more stable than complex (4). Fe(III) complex exhibits higher antibacterial and antifungal activities than other metal complexes. Chelate (6) exhibits the highest rate of germination in wheat.