Segunda entrada 2009 y Abstract para Annual Poster Day
Durante este mes he tenido varias complicaciones de salud las cuales no me han permitido un gran avance en el laboratorio. De igual manera catalogo con un 2 mi progreso en el mismo. Como ya saben mis compuestos son bien difíciles para lograr su solubilidad y he estado leyendo “papers” y estudiando con la Dra. Cadiz la manera de solubilizar los mismos. La profesora me sugirió hacer un compuesto de NaBr y K2PtCl4 el cual se preparó de la siguiente manera:
- Se pesó 0.5 g de NaBr, 0.5 g de K2PtCl4 y se disolvieron en 10 mL de agua desionizada.
- Se preparó una solución de [N(C3H5)4]Br (tetraetilamonium bromide) disolviendo 0.5 g de la sal en 5 mL de agua desionizada.
- A esta solución se le añadió la preparada previamente con NaBr y K2PtCl4 en un “beaker” apropiado.
- El “beaker” se colocó en contacto con vapor de agua por dos horas y media. Para esto se utilizó un recipiente de metal con tapa de anillos lleno de agua en un “hot plate”.
- Al paso de las dos horas y media ya había precipitado todo el compuesto.
Actualmente este compuesto se encuentra en la nevera del laboratorio, el mismo tengo que filtrarlo y pesarlo para poder calcular su rendimiento. Adicional a este proceso, la próxima semana voy a asistir al Taller de NMR que ofrecerá Aracelis Cardona del departamento de química. Me interesa mucho tomar este taller ya que a los compuestos de tiazol y tetracloroplatinato de potasio se les han hecho estudios NMR pero ninguno por mí misma. De esta manera experimetaré yo misma el proceso.
ABSTRACT
Synthesis of Platinum(II) Complexes of the Type cis-[PtCl2(Am2)] (Am = thiazole and alkylthiazoles)
Iriselies Meléndez Rodríguez, Mayra E. Cádiz.
Chemical Engineering Program, University of Puerto Rico, Mayagüez Campus
Department of Chemistry, University of Puerto Rico, Mayagüez Campus
Cisplatin, cis-[PtCl2(NH3)2], is an anticancer drug that acts inhibiting the proliferation of tumor cells by interfering with DNA replication and transcription. This drug is widely used to treat cancers such as metastatic testicle, metastatic ovary, and metastatic bladder, among others. The purpose of this project is to substitute both ammine (NH3) ligands in cisplatin with more bulky ligands to retard the substitution of chloride ions, and as a result, to reduce undesired reactions between platinum and cellular components such as glutathione. Because the thiazole molecule is present in various platinum anti-tumor compounds, it was used in this work as a nitrogen donor or amine. The following compounds with general formula cis-[PtCl2(Am)2] were prepared from K2PtCl4 by the direct reaction with the ligand in a water/ethanol mixture (3:1 v/v): cis-[PtCl2(thiazole)2] (1), cis-[PtCl2(2,4,5-trimethylthiazole)2] (2), cis-[PtCl2(4-methylthiazole)2] (3), and cis-[PtCl2(5-methylthiazole)2] (4). The complexes were characterized by elemental analysis, infrared and Raman spectroscopy. In addition, we characterized the cis-[PtCl2(2,4-dimethylthiazole)2] (5) complex, which was previously prepared in our laboratory. The yields went from 20% to 58%, based on K2PtCl4. The infrared spectra of complexes present the characteristic C-H, C=C and C=S bands of thiazoles. Spectra of (3) and (4) were very similar since they only differ in the position of the methyl group. Samples of cis-[PtCl2(thiazole)2] and cis-[PtCl2(4-methylthiazole)2] were analyzed for C and H, and results agree with theoretical values (less than 1% error). The samples containing complex (2) and (4) require additional purification. The Raman spectra of the pure complexes (1), (3) and (5), show the characteristic Pt-Cl band at 345, 338 and 354 cm-1, respectively. A series of structurally related platinum complexes have been successfully prepared and a study of their relative reactivity toward biological targets is underway.
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