Synthesis, Structural Insights, and Biological Evaluation of N ‐(4‐Methoxyphenyl)‐2‐oxopropanamide 4‐allylthiosemicarbazone and Its Copper(II), Nickel(II), and Iron(III) Coordination Compounds
Ianina Graur, Vasilii Graur, Victor Tsapkov, Olga Garbuz, Elena Melnic, Pavlina Bourosh, Carolina Lozan-Tirsu, Greta Balan, Aurelian GuleaA novel compound, N ‐(4‐methoxyphenyl)‐2‐oxopropanamide 4‐allylthiosemicarbazone ( HL ), together with 11 coordination complexes, was obtained and investigated: [Cu(L)(Cl 2 CHCOO)] 2 ( 1 ), [Cu(L)NO 3 ] ( 2 ), [Cu(A) (L)]NO 3 ( A = 1,10‐phenanthroline ( 3 ), 2,2’‐bipyridine ( 4 )), [Cu(A)(L)(NO 3 )] ( A = pyridine ( 5 ), 3‐methylpyridine ( 6 ), 4‐methylpyridine ( 7 ), 3,4‐dimethylpyridine ( 8 )), [Fe(L) 2 ]NO 3 ( 9 ), [Ni(HL) 2 ]Cl 2 ( 10 ), [Ni(HL) 2 ](NO 3 ) 2 ( 11 ). Their composition and structure were confirmed by elemental analysis and FTIR, as well as 1 H and 13 C NMR spectroscopy. Additionally, the crystal structures of HL and сomplexes 1, 7, 8, and 10 were determined by single‐crystal X‐ray diffraction. Biological assays demonstrated that coordination of HL with copper(II) enhanced the antimicrobial and antifungal properties of the resulting complexes, with further improvement upon incorporation of N ‐heteroaromatic bases into the copper(II) coordination sphere. Binding of HL to nickel(II) and iron(III) centers resulted in an increased antioxidant response against ABTS •+ . Mixed‐ligand copper(II) complexes also exhibited superior antioxidant capacity compared to their copper(II) complex precursors.