Estudos estruturais em compostos de interesse farmacológicos contendo átomos pesados / Structural studies of pharmacological interested compound containing heavy atoms
AUTOR(ES)
Sauli dos Santos Junior
DATA DE PUBLICAÇÃO
2004
RESUMO
The determination of the three-dimensional structures of heavy-metal chelates and of some potentially useful chelating agents is a very important to01 in the study of complexes that may act as antidotes against poisoning by ingestion of heavy metals. A detailed knowledge of these complexes is expected to assist in the design of molecular structures and procedures that are more effective in counteracting the life threatening processes inevitably developed by individuals with chronic heavy-metal intoxication. Within this framework a series of dimethylthallium(III) complexes were studied. Here we present complexes of the type [TlMe2L], where L=2-mercapto-3- pyridine carboxylic acid(I), 6-mercapto-3-pyridine-methoxycarboxylate(II), 2-mercapto-3-pyridine-methoxycarboxylate(III), 6-mercapto-3-pyridineethoxycarboxylate(IV) and 2-mercapto-3-pyridine-ethoxycarboxylate(V). The study of the supramolecular arrangement of these complexes shows that, in spite of the differences in space group symmetry and substituents in the ligand, the crystals packing are remarkably similar. The complexes form infinite polymers in one, two and three dimensions, based upon TI-S, T1-0 e T1-N covalent bonds and intermolecular secondary interactions. The complexes also present strong hydrogen bond intermolecular interactions. There are many forms of corrections to the data collected in a single crystal X-ray diffration experiment. During the data reduction many corrections take place, such as: Lorentz, polarization, absorption and eventualy corrections for the deterioration of the sample. The absorption correction is strongly recommended for crystals with strong absorbers in its structural form. The effect of the absorption of the X rays has been studied in crystalline samples, as well as a comparison between the result obtained from the different available methods of absorption corrections. This work that showed different forms of absorption correction, made significant differences in the merit figures, peak and hole of residual charge density, as well as the anisotropic displacements parameters. Bonds distances and angles, on the other hand, did not change significantly.
ASSUNTO(S)
metal complexes dimethyl-thaliun complexos metálicos correção por obsorção dimetil-tálio absorption correction crystal structure estrutura cristalina
