Synthesis, characterization and in vitro cytotoxicity of Co(II) complexes with N6-substituted adenine derivatives:: X-ray structures of 6-(4-chlorobenzylamino)purin-di-ium diperchlorate dihydrate and [Co6(μ-L6)4Cl8(DMSO)10] • 4DMSO

Cobalt(II) complexes of the composition [Co(L-1)Cl(H2O)(2)]center dot H2O (1), [Co(L-2)Cl(H2O)(2)]center dot 2H(2)O (2), [Co(L-3)Cl(H2O)(2)]center dot H2O (3) [Co(L-4)Cl(H2O)(2)]center dot H2O (4), [Co(L-5)Cl(H2O)(2)] center dot H2O (5) and [Co(L-6)Cl(H2O)(2)]center dot H2O (6), where HL1 = 6-(3-chlorobenzylamino)purine, HL2 = 6-(4-chlorobenzylamino)purine, HL3 = 6-(2,3-dimethoxybenzylamino)purine, HL4 = 6-(3,4-dimethoxybenzylamino)purine. HL5 = 6-(3-fluorobenzylamino)purine and HL6 = 6-(4-fluorobenzylamino)purine, have been prepared. The compounds have been characterized by elemental analyses, ES+ mass, UN-Vis, IR and NMR spectroscopies, magnetic measurements, molar conductances and thermogravimetric analysis as mononuclear tetrahedral high-spin cobalt(II) complexes. In vitro cytotoxicities of the complexes were tested by a Calcein AM assay against the following human tumour cell lines: malignant melanoma (G361), chronic myelogenous erythroleukemia, (K562), osteogenic sarcoma (HOS) and breast adenocarcinoma (MCF7). The molecular structures of 6-(4-chlorobenzylamino)purin-di-ium diperchlorate dihydrate, [H2+ L-2](ClO4)(2) center dot 2H(2)O, and a hexanuclear Co(II) complex, [Co-6(mu-L-6)(4)Cl-8(DMSO)(10)]center dot 4DMSO (7). have been determined by a single crystal X-ray analysis. To elucidate the manner of the organic ligand coordination to cobalt, the geometry of the complex 2 was optimized Using DFT calculations at the B3LYP/6-311+G* level of the theory. (c) 2005 Elsevier Ltd. All rights reserved.