Synthesis and Structures of Ferrocenylmethyl Leucine and a Copper(II) Complex Based on it

Ferrocenylmethyl leucine (HL) and a copper(II) complex based on it [Cu(MeOH)LCl]_n·nH₂O (1) are obtained for the first time. The compounds are characterized by the elemental analysis, powder X-ray diffraction, and IR spectroscopy. The ligand structure is confirmed by NMR spectroscopy, and the structure of [Cu(MeOH)LCl]_n complex (1a) is determined by the single crystal X-ray diffraction analysis. The complex obtained is a polymeric chain due to the chelate-bridging function of tetradentate L^– coordinated by oxygen atoms of the carboxylate group and the nitrogen atom of the amino group. The stability of complex 1 is studied in methanol and an aqueous solution for 48 h. Cytotoxicity of the HL ligand and the copper(II) complex is investigated against MCF7 (breast adenocarcinoma) and MRC5 (lung fibroblast) cell lines. The complex is shown to exhibit the cytostatic activity in the concentration range of 5-50 µM against both cell lines.