Synthesis, characterization, and in vitro antiproliferative and antibacterial studies of tetraazamacrocyclic complexes of Co(II) and Cu(II) with pyromellitic acid

Abstract

AbstrcatNew cationic tetranuclear Co(II) and neutral binuclear Cu(II) complexes with tpmc (N,N,N,N-tetrakis-(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane) and bridging pyromellitate ligand pma (tetraanion 1,2,4,5-benzenetetracarboxylic acid) were isolated. The composition of the compounds is proposed based on elemental analyses (C, H, N, M=Cu, Co), molar conductivity determination, UV-Vis, FTIR, EPR, LC-MS and reflectance spectroscopy, magnetic measurements, cyclic voltammetry, as well as TG and DTA. It is proposed that in [Co-4(pma)(tpmc)(2)](ClO4)(4)6H(2)O (1), cobalt(II) is six-coordinate out of cyclam rings and one OCO- from pma participates in coordination with one Co(II). In the case of [Cu-2(pma)tpmc].8H(2)O (2), one OCO- from pma bridges two Cu(II). The cytotoxic activity of 1 and 2 was tested against tumor cell lines human cervix adenocarcinoma (HeLa), estrogen-receptor-positive human breast cancer (MCF-7), human myelogenous leukemia (K562), and the human Caucasian Burkitt's lymphoma (Ramos). The IC50 values for 1 and 2 were within the range 44.66 +/- 2.39 to 152.40 +/- 2.28M, and from 140.88 +/- 3.51 to 192.05 +/- 2.09M, respectively. Both 1 and 2 were tested for antimicrobial activity. We determined that minimal inhibitory concentration for 1 against Staphylococcus aureus, Bacillus subtilis, and Klebsiella pneumoniae was 25mM. Complex 2 did not express activity against tested microbial strains.