Synthesis, characterization and antiproliferative behavior of tricarbonyl complexes of rhenium(I) with some 6-amino-5-nitrosouracil derivatives:: Crystal structure of fac-[ReCl(CO)3(DANU-N5,O4)] (DANU=6-amino-1, 3-dimethyl-5-nitro souracil)

New complexes of rhenium(l) with some 5-nitrosopyrimidines with general formula [ReCl(CO)(3)L] have been prepared and characterized by elemental analysis, conductivity measurements, IR and H-1, C-13 and N-15 NMR spectroscopic methods. The complexes appear to be monomeric and the pyrimidine ligands act in a neutral form. The structure of [ReCl(CO)(3)(DANU)] center dot CH3CN has been solved by X-ray diffraction. The coordination environment around the Re(I) may be described as a distorted octahedron in which the ligand behaves in a bidentate fashion through N5 and 04 atoms, making a five-membered chelate ring. The coordination sphere is completed with three carbonyl groups in fac-arrangement and one chlorine atom. The evaluation of the antiproliferative behavior against five human tumor cell lines (human breast cancer MCF-7 and EVSA-T, human neuroblastoma NB69, human glioma H4 and human bladder carcinoma cell line ECV) suggested a modulator behavior of cell growth at low concentrations due to their estrogenic-like characteristics. (c) 2005 Elsevier Inc. All rights reserved.