From Design to Bioactivity: 2‐Benzoylpyridine 4‐(bicyclo[2.2.1]hept‐2‐yl)thiosemicarbazone and Its 3 <i>d</i> Metal Coordination Compounds

The new 2-benzoylpyridine 4-(bicyclo[2.2.1]hept-2-yl)thiosemicarbazone (HL) and its copper(II), nickel(II), cobalt(III), and iron(III) coordination compounds [Cu(L)Cl] (1), [Cu(L)NO₃] (2), {[Cu(L)(Cl₂CHCOO)]}_n (3), [Ni(HL)₂](NO₃)₂ (4), [Fe(L)₂]NO₃ (5), [Co(L)₂]NO₃ (6) were obtained. The thiosemicarbazone HL was studied using ¹H, ¹³C NMR, and FTIR spectroscopy. All the obtained 3d metal coordination compounds were characterized by elemental analysis and FTIR spectroscopy. The single-crystal X-ray diffraction analysis was used to determine the crystal structures of HL and complex 3. The study of antibacterial activity revealed that coordination of the thiosemicarbazone HL to the metal ions leads to an increase in activity. Whereas in the case of antifungal activity, the effect is the opposite-the activity either remains at the same level or decreases. Most of the complexes exhibited activity that surpassed the results obtained for the standard drugs Furacillinum, Nystatin, and Fluconazole.