Versatile CoII and NiII mononuclear complexes with furoate/thiophencarboxylate anions and 3,5-dimethylpyrazole– Synthesis, structure, magnetic, catalytic and antimycobacterial properties

Series of complexes of the composition [M(L)₂(Hdmpz)_n] (L = fur, M = Co^II, n = 2 (1), n = 4 (2), M = Ni^II, n = 2 (3), L = tph, M = Co^II, n = 2 (4), M = Ni^II, n = 2 (5), n = 4 (6)) has been obtained by interaction of cobalt^II and nickel^II acetates with 3-furancarboxylic (Hfur) or 2-thiophencarboxylic (Htph) acids, followed by the addition of 3,5-dimethylpyrazole (Hdmpz). According to the X-ray data in complex 1–6, metal atoms are surrounded by carboxylate anions and two or four monodentately coordinated Hdmpz molecules. Additional stabilization of the complexes is carried out by the inter- and intramolecular hydrogen bonds. Co and Ni catalysts obtained by chemical activation of 1 and 3 exhibit high catalytic activity in a continuous dicyclopentadiene (DCPD) hydrogenation process at atmospheric hydrogen pressure. Slow relaxation of magnetization has been found for complexes by use of ac-magnetometry for compounds 1 and 4 at 1000 Oe dc-field in contrast with 2, 3, 5, 6 exhibiting no slow magnetic relaxation. Biological activity of 1–6 has been determined against a non-pathogenic strain of Mycobacterium smegmatis.