A new dialdehyde N, N’-bis(5-formylpyrrol-2-ylmethyl) homopiperazine (A) was synthesized by the Man- nich reaction of pyrrole 2-carbaldehyde, formaldehyde and homopiperazine in the presence of hydrochlo- ric acid. From the direct reaction of A with 1,3-diaminopropane or 1,4- diaminobutane two new macro- cyclic Schiffbase ligands were obtained, L 1 and L 2 , respectively. The reaction of these ligands with Ni(II), Co(II) and Pt(II) metal ions results in formation of the relevant macrocyclic Schiffbase complexes. Com- pounds were characterized by FT-IR, elemental analysis, mass spectrometry, UV-Vis and, in the case of the ligands, by 1 H and 13 C-NMR. The crystal structure of the complex [Ni 2 L 2 (CH 3 O)]ClO 4 (4) showed a binuclear macro-cyclic structure, with each Ni coordinated by three nitrogen atoms from the ligand and by a methoxide bridging the two metal centers. The cytotoxic activities of these compounds indicated that the ligands, and some of the complexes, have high anti-proliferative effect towards A549 and HeLa cells, but not HT29 cells. Pt complex with L 1 and L 2 displayed stronger anti-proliferative activity toward HeLa (IC50 = 11 μM for both of them and A549 IC50 = 7 μM and 8 μM, respectively) relative to L 1 and L 2 . In addition, the cytotoxic effects of the compounds were assayed in rat fibroblast cells as a model of the normal cell, however none of them showed any significant cytotoxic effects. Thereby upholding the potential of these compounds for further development as chemotherapeutic agents.
