Cutting-edge green synthesis and characterization of novel Ni(ii) and Co(ii) fluoroimine complexes: a multifaceted evaluation of anticancer, antioxidant, and antimicrobial activities

Abstract

A novel Schiff base ligand, benzyl 2-(2-fluorobenzylidene)hydrazine-1-carbodithioate (L₁H), and its Co(II) and Ni(II) complexes (1 : 1 and 1 : 2 metal–ligand ratios) were synthesized using a green, microwave-assisted approach. Conventional thermal synthesis was also employed for comparison, revealing that the microwave-assisted method significantly enhanced reaction efficiency, yield, and sustainability. The synthesized compounds were comprehensively characterized via ¹H-NMR, ESI-MS, PXRD, UV-Vis, FT-IR, elemental analysis, magnetic moment measurements, and cyclic voltammetry, confirming a bidentate N–S coordination mode and an octahedral geometry around the metal centers. The antimicrobial evaluation demonstrated enhanced antibacterial and antifungal activities of the metal complexes compared to the free ligand, with [Ni(L₁)(OAc)(H₂O)₃] exhibiting superior potency. Cytotoxicity studies against MCF-7 and HeLa cancer cell lines using the MTT assay revealed that [Ni(L₁)₂(H₂O)₂] exhibited the highest efficacy against HeLa cells, with a selectivity index value of 7.22 and an IC₅₀ value of 55.28 μg, indicating preferential toxicity toward malignant cells while sparing normal cells. Additionally, DPPH and ABTS assays confirmed that Ni(II) complexes possess significant antioxidant activity, highlighting their therapeutic potential. These findings underscore the biomedical significance of these complexes, making them promising candidates for further pharmacological exploration.