Synthesis, Characterization and Biological Studies of Ferrocenyl Ureas & Thioureas

Abstract

Series of ferrocene substituted organometallic thioureas and ureas of general formula [C 5 H 5 FeC 5 H 4 C 6 H 3 (R)NHC(X)NHR`] where, R = H, CH 3 , OCH 3 or Cl, R` = alkyl/aryl groups and X = O or S, have been synthesized and characterized by using elemental analysis, FT-IR, multinuclear ( 1 H and 13 C) NMR spectroscopy and UV-Visible spectroscopy. Single crystal XRD was used for structural elucidation of some of the synthesized intermediate and end products. In all crystal structures free cyclopendienyl (Cp) ring found to be disordered over two sets of atoms. Based on the single crystal X-ray analysis most of the synthesized compounds were found to be stabilized by intermolecular as well as intramolecular hydrogen bonding and secondary non-covalent interactions. These intermolecular interactions permeate these molecules to form supera-molecular structures. The synthesized intermediates and the end products were studied for the interaction with modal bio-mimetic micelle membranes by probing with 1 H-NMR and UV-Visible spectroscopy. Membrane penetration studies have been carried out for some compounds with model lipid membrane interfaces prepared from SDS and TTAB surfactants using 1 H NMR and UV-Vis spectroscopic techniques. Results show the presence of these molecules in the interfacial regions of the self assembled systems. These studies justify the lipophilic character of these compounds as their ability to penetrate into the modal membranes. Primarily these compounds were screened for their DNA binding behavior and antioxidant activity to evaluate their anti-cancer potency. Ferrocenyl ureas exhibited better anti-oxidant activity than the respective thioureas in general and compound B u 6 was found to be the most active with IC 50 = 11.94 ± 0.05 μM (IC 50 for standard thiourea is 30.53 ± 0.1 μM). DNA binding studies based on UV-Visible spectrophotometric titration shows the potential of these organometallic compounds as an anti-cancer agents. In ferrocenyl thioureas, the induction of nitro group found to increase the binding ability of these compounds with DNA in these titrations. And E t 6 was found to be the most interacting compound among the tested ones with binding constant of Kb = 10810 M -1 .