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Moura C.,Instituto Tecnologico e Nuclear Estrada Nacional | Gano L.,Instituto Tecnologico e Nuclear Estrada Nacional | Santos I.C.,Instituto Tecnologico e Nuclear Estrada Nacional | Paulo A.,Instituto Tecnologico e Nuclear Estrada Nacional | Santos I.,Instituto Tecnologico e Nuclear Estrada Nacional
Current Radiopharmaceuticals | Year: 2012

The new dihydrobis(azolyl)borate ligand Na[H 2B(tim Me)(3,5-Me 2pz)] (L 1) was synthesized and used to prepare the complexes fac-[M(κ 3-H(μ-H)B(tim Me)(3,5-Me 2-pz))(CO) 3] (M = Re (4), 99mTc (4a)). L 1 and 4 were characterized by common analytical techniques, including X-ray diffraction analysis for 4. The successful synthesis of complex 4a, obtained with high radiochemical purity, has shown for the first time that dihydrobis(azolyl)borate ligands combining 2-mercaptoimidazolyl and pyrazolyl rings are capable of stabilizing the fac-[ 99mTc(CO) 3] + unit. Complex 4a displays a high in vitro stability, in PBS (pH 7.4), indicating that the B-H. 99mTc bond is retained even under physiological conditions. Biodistribution studies in mice have shown that 4a can cross the blood-brain barrier, emerging as a good alternative for the design of radiopharmaceuticals for brain imaging. © 2012 Bentham Science Publishers.

Gama S.,Instituto Tecnologico e Nuclear Estrada Nacional | Santos I.,Instituto Tecnologico e Nuclear Estrada Nacional | Mendes F.,Instituto Tecnologico e Nuclear Estrada Nacional | Marques F.,Instituto Tecnologico e Nuclear Estrada Nacional | And 5 more authors.
Journal of Inorganic Biochemistry | Year: 2011

Tridentate pyrazole-containing ligands of the Schiff base type, SalPz - HL1, Cl2SalPz - HL2 and I2SalPz - HL3, were used to prepare a series of new Cu(II) complexes (CuSalPz - 1, CuCl2SalPz - 2 and CuI2SalPz - 3). These new complexes have been studied by different analytical techniques (electrospray ionization mass spectrometry (ESI-MS), elemental analysis, FT-IR and EPR). The spectroscopic properties of 1-3 are consistent with the formation of Cu(II) complexes coordinated by monoanionic and tridentate (N,N,O)-chelators, behaving as monomeric species in aqueous solution, as shown by EPR studies. Crystals of 2 and 3, obtained by slow concentration of methanolic solutions of the compounds, were also analyzed by X-ray diffraction analysis. The X-ray structural study has shown that 2 crystallized as a dinuclear compound, [Cu2(μ-Cl) 2(Cl2SalPz)2], while the solid state structure determined for 3 is best described by monomeric units of [CuCl(I 2SalPz)] displaying short Cu•••Cl intermolecular contacts. The in vitro evaluation of 1-3 comprised the study of their DNA-cleaving ability using plasmid DNA and the assessment of their cytotoxic activity against several human cancer cell lines (PC-3 prostate, MCF-7 breast and A2780 and A2780cisR-ovary). The studies with plasmid DNA have shown that 2 and 3 induce extensive DNA cleavage in the presence of different additives. The cytotoxic activity of 2 and 3 is comparable to the one presented by cisplatin, with the exception of the A2780 cell line where cisplatin is more active. It has been found that the introduction of halogen substituents in the phenolate rings of the chelators enhanced the cytotoxicity of the respective Cu(II) complexes. © 2011 Elsevier Inc.

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