Bio functional molecular complexes, ferrocenyl hydrazone based binuclear Cu (II) derivatives: Synthesis, spectral, DNA/BSA binding & in-silico analyses

As a first stage intermediate, designing mononuclear complexes of amine-based phenolic derivatives employing Cu (II) acetate as a central metal ion in a 1:2:1 ratio. In a methanolic solution treated with 1,1′-diacetyl ferrocene dihydrazone and Cu (II) perchlorate hexahydrate to generate a new group of ferrocene based macrocyclic binuclear Cu (II) complexes. To characterize the macrocyclic complexes, physico-chemical studies such as FT-IR, UV–vis, and photoluminescence were used. The binuclear Cu(II) complex [Cu₂L¹] exhibits two quasi-reversible reduction waves in the potential range The binuclear complex [Cu₂L¹] has two waves of virtually reversible reduction in the potential range of E¹_pc = −1.01 V and E²_pc = −1.37 V in the electrochemical investigation. They show a reduction process that involves two one-electron reductions in steps. The ferrocenyl group of the complexes shows one-electron ferrocene/ferrocenium redox activity, although with differing peak potentials. CT-DNA was used to study DNA binding utilizing spectroscopic techniques such as Circular Dichroism, UV–vis, and Fluorescence. The binding constant (K_b) values for the series of complexes range from 1.3x10⁵ to 5.8 × 10⁵ M⁻¹. The metal complexes all interacted with CT-DNA by an intercalative form of binding, according to fluorescence spectrum analyses. BSA protein binding, on the other hand, indicates a quenching manner of interaction with the binuclear complex system, with binding constants of 1.77 × 10⁶, 1.65 × 10⁶, 2 × 10⁶, 4.8 × 10⁶ and 5.12 × 10⁶ M⁻¹. Molecular docking analysis was used to support and augment the experimental biological studies. Intercalation was seen during the docking of 1BNA with a metal complex due to multiple hydrogen bonding interactions. The ferrocene heterocyclic ring and the naphthyl group of complexes interacted with the BSA protein's ARG and TYR systems.