Síntese e caracterização de nanocomplexos de lantanídeos com mesoiônicos: perspectivas para marcadores tumorais imunohistoquímicos e fármacos.

Abstract

The solids obtained in nanometric scale has been attracted the technological and scientific interest due to the significant modifications observed on their physical and chemical properties which increases the technological applications. In this work, four nanocomplex materials were synthesized: Ln(MI)3.3H2O where, Ln = Er or Eu and MI = 5(4-chlorophenyl)-3-phenyl-1,3,4-thiodiazole-2-tiolat (MI-1) or 5(4-chlorophenyl)-3-methyl-4-phenyl-1,3-thioazole-2-thiolate (MI-2). These complexes were characterized using physico-chemical, spectroscopic, thermal and structural techniques. To synthesize the complexes, it was used a LnCl3 ethanolic solution mixed with the mesoionic, maintained under agitation and at a constant temperature at 65oC and refluxed for a period of four hours. It was observed a good agreement between the experimental and calculated results of the C, H and N elemental analysis of Er(MI-1)3.3H2O, Eu(MI-1)3.3H2O, Er(MI-2)3.3H2O and Eu(MI-2)3.3H2O. The IR spectra indicates that the coordination of the mesoionic compounds with cations Eu+3 and Er+3, must happen probably because of the exocyclic sulfur atom and it can be perceived a considerable displacement in the carbon-sulfur (C-S-) ligation. The RMN 1H spectra suggested the presence of aromatic hydrogen evidenced in the mesoionic compounds. Through the RMN 13C (APT), it was possible to recognize the hydrogenation standard corresponding to each carbon atom. It can be safely attributed the carbon chemical displacement (C-2) and (C-5) of the mesoionic ring. In the UV-visible absorption spectra of the UV the complexes bands are displaced comparing to the mesoionic compound bands. It can be possible to attribute the insertion of the lanthanide cations to the modification of the absorption bands, once the complexes presented energies at inferior length. The MI-1 and MI-2 compounds emission spectra and the complexes Eu(MI-1)3.3H2O and Er(MI-2)3.3H2O presented a behavior similar to a large emission band between 560 and 720 nm. It was not possible to observe the emission bands of the lanthanide ions. The TG/DTG curves indicate that the mesoionic compounds were decomposed in five levels, with a different behavior of the Er(MI-1)3.3H2O, Eu(MI-1)3.3H2O, Er(MI-2)3.3H2O and Eu(MI-2)3.3H2O, which decomposition occurred in 5,4,7 and 6 steps, respectively. The complexes synthesized with Eu presented a higher thermal stability than the ones that used Er, independently of the kind of mesoionic compound that was used. The DSC curves showed that the studied complexes begin the thermal decomposition reaction before the fusion, in the solid state. The x-ray diffractograms of the complexes and mesoionic compounds present more than a level, with crystalline characteristics and crystallite size inferior to 60nm.