Biologically active meta-substituted ferrocenyl nitro and amino complexes: Synthesis, structural elucidation, and DFT calculations

Abstract

In our search for new anticancer and DNA interacting drugs, ferrocene-incorporated nitro 1a-1b and aniline compounds 2a-2b were successfully synthesized and characterized by various physicochemical and spectroscopic methods. The proposed nitrophenylferrocenes were prepared by the coupling reaction between ferrocene and the diazonium salts of different nitroanilines using a phase transfer catalyst. In the subsequent reactions, these nitro compounds were reduced to the corresponding anilines using zinc dust/ammonium formate. Charge distribution and the HOMO/LUMO energies of the optimized structures that were calculated using the DFT/B3LYP method correlate well with the experimentally determined redox potential values. The nature and extent of binding of these complexes with the biomolecule, SS-DNA was examined by cyclic voltammetry, UV–Vis spectroscopy, and viscometry; the complexes exhibited good binding strengths to DNA. The diffusion coefficients of the compound-DNA adducts for all the complexes are lower than that of the free compound and the small values of the binding site sizes also indicate the dominance of electrostatic interactions. These compounds have also been demonstrated to be decent candidates in terms of free radical scavenging, protein kinase inhibition, and cytotoxicity.