Estudio termodinámico de pirogalolarenos aromáticos y sus complejos de Cu(II) y Pb(II)

Abstract

En este trabajo se obtuvieron y caracterizaron tres pirogalolarenos (PgEter, PgAmida y PgAC), uno de ellos (PgAmida) es un nuevo compuesto. Se determinaron propiedades fisicoquímicas como solubilidad, entalpía de solución, compresibilidades y densidades en solución. Además, se determinaron las estructuras de los complejos con Cu2+ y Pb2+ por medio de espectroscopia EXAFS, FT-IR, masas y RMN. Adicionalmente se determinaron los valores de constante de estabilidad por medio de espectrofotometría UV-Vis para los complejos obtenidos. El estudio de los pirogalolarenos reveló que se obtuvieron desolvatados y en conformación ?Silla?. Los estudios fisicoquímicos muestran que se dan fuertes interacciones de tipo puente de hidrógeno en los compuestos no acetilados, que conducen a la formación de agregados en DMF, mientras que en DMSO estos agregados se rompen dando lugar a interacciones fuertes soluto-solvente. En el derivado acetilado se ven favorecidas las interacciones de tipo van der Waals en solución de ACN. Los complejos entre PgEter y PgAmida con Cu2+ solamente pudieron obtenerse en DMF y forman estructuras capsulares estables, que fueron caracterizadas como de tipo hexamérico. Con Pb2+ se forman complejos donde se conserva la estructura de silla y el ion metálico presenta geometría tripodal. Los complejos PgAc con Cu2+ y Pb2+ también conservan la estructura de silla. Se encontró que los complejos obtenidos son relativamente estables. Se obtuvieron monocapas de Langmuir estables para PgAc, en donde existe una alta probabilidad de cambio conformacional de silla a corona, y se determinó el acomplejamiento en monocapa con Ca2+ y Cd2+, mientras que no se detectó acomplejamiento con iones monovalentes Na+ y K+

In this work three pyrogallolarenes have been obtained and characterized (PgEter, PgAmida, PgAc), one of them (PgAmida) is a new compound. Their physicochemical properties such as solubility, solution enthalpy, compressibility, and solution densities were measured and calculated. Also, it was obtained their complexes with Cu2+ and Pb2+, and their structures were obtained through different spectroscopic methods including EXAFS, FT-IR, mass spectrometry and NMR. In addition, the stability constants for each one complex were obtained by means of UV-Vis spectrophotometry, using the Hyperquad software. The obtained pyrogallolarenes were characterized as non-solvated molecules, and in the saddle chair conformation. From physicochemical experiments, a strong hydrogen bond interaction conducting to aggregate structures were deduced for non-acetylated derivatives (PgEter, PgAmida) in DMF solution, while in DMSO it was obtained a disaggregation to form solute-solvent interactions. On the other hand, the peracetylated derivative (PgAc) exhibits high solute-solvent interaction in ACN through van der Waals interactions. In this work three pyrogallolarenes have been obtained and characterized (PgEter, PgAmida, PgAc), one of them (PgAmida) is a new compound. Their physicochemical properties such as solubility, solution enthalpy, compressibility, and solution densities were measured and calculated. Also, it was obtained their complexes with Cu2+ and Pb2+, and their structures were obtained through different spectroscopic methods including EXAFS, FT-IR, mass spectrometry and NMR. In addition, the stability constants for each one complex were obtained by means of UV-Vis spectrophotometry, using the Hyperquad software. The obtained pyrogallolarenes were characterized as non-solvated molecules, and in the saddle chair conformation. From physicochemical experiments, a strong hydrogen bond interaction conducting to aggregate structures were deduced for non-acetylated derivatives (PgEter, PgAmida) in DMF solution, while in DMSO it was obtained a disaggregation to form solute-solvent interactions. On the other hand, the peracetylated derivative (PgAc) exhibits high solute-solvent interaction in ACN through van der Waals interactions