Synthesis, characterization, antibacterial properties and in silico molecular docking of binuclear copper(II) complexes with planar aromatic derivatives of aroyl hydrazine ligands

Two binucleating ligands were prepared through the modification of aroyl hydrazines and used in the synthesis of novel ternary dicopper(II) complexes (1a–1d and 2a–2c), possessing the general formula [Cu₂(A)L(CH₃COO)_n]. The primary ligands, referred to as L, encompass N-Benzoyl-N′-[1-(5-acetyl-2,4-dihydroxy-phenyl)-ethylidene]-hydrazine (L1), N-phenylacetyl-N′-[1-(5-acetyl-2,4-dihydroxy-phenyl)-ethylidene]-hydrazine (L2) and secondary ligand A, including 2,2′-bipyridine (a) or 1,10-phenanthroline (b) or 2-hydroxybenzoic acid (c) or 5-bromo-2-hydroxybenzoic acid (d), yielding the respective complexes. Comprehensive characterization of the complexes involved elemental analysis as well as various spectroscopic techniques. Among the complexes, 1d exhibited weak antiferromagnetic coupling, while the other complexes displayed ferromagnetic coupling. Evaluation of in vitro antibacterial activity against gram-positive strains such as S. aureus and B. megaterium, as well as gram-negative strains including S. typhi, S. marsescens, and P. vulgaris, revealed the notable impact of metal ions. Remarkably, the complexes enhanced good antibacterial efficacy against gram-positive strains compared to that of ligands. Furthermore, an assessment of the in vitro anti-proliferative properties of both the ligands and complexes was also undertaken. Again an enhanced activity was observed with complexes over the ligands. Molecular docking accentuated the substantial binding affinities of specific complexes (1a, 1b, 1d, 2b) toward the cyclooxygenase-2 inhibitor (3LN1) receptor. These in silico findings further validate the potential of the identified complexes (1a, 1b, 1d, 2b) as promising COX-2 inhibitors.

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