Synthesis, structure and biological activities of cobalt(II) and zinc(II) coordination compounds with 2-benzimidazole derivatives

In this work we present the synthesis, structural and spectroscopic characterisation of a series of cobalt(II) and zinc(II) coordination compounds with benzimidazole (bz) and its 2-benzimidazole derivatives: 2-aminobenzimidazole (2ab), albendazole (abz) and tris(2-benzimidazolylmethyl)amine (ntb). The compounds were evaluated for their in vitro antimicrobial activity against Staphylococcus aureus, Micrococcus luteus, Salmonella typhi, Pseudomonas aeruginosa, Escherichia coli and Proteus vulgaris. Their cytotoxic activity was also evaluated using human cancer lines, HeLa, HCT-15 and SKLU-1. The halide tetrahedral compounds [Co(bz)(2)Br-2] 3, [Zn(2ab)(2)Cl-2]center dot 0.5H(2)O 11, [Co(abz)Cl-2(H2O)]center dot 3H(2)O 14, [Co(abz)Br-2(H2O)] 15, [Zn(abz)Cl-2(H2O)]center dot 3H(2)O 17 and [Zn(abz) Br-2(H2O)] center dot H2O 18 displayed similar minimal inhibition concentration (MIC) values against Micrococcus luteus and Escherichia coli, comparable to those of amoxicillin and chloramphenicol. Additionally, 11 showed a wide range of activity towards Gram(+) and Gram(-) microorganisms. The tetradentate ntb and its trigonal bipyramidal cobalt(II) and zinc(II) compounds were active, regardless of the anion present in the complex. Compound [Co(abz)Cl-2(H2O)] center dot 3H(2)O 14 showed promising activity in HeLa cells, while (Co(ntb)Br]Br center dot H2O 21 inhibited Hela and HCT-15 cell lines. (C) 2008 Elsevier Inc. All rights reserved.