Estudo da estabilidade do polímero de coordenação ZIF água e solventes orgânicos

Abstract

IUPAC (International Union of Pureand Applied Chemistry), defines a coordination polymer as a coordination compound that expands, through coordinated bonds, in a unidimensional, bidimensional or three-dimensional way. Among these coordination polymers are the ZIFs (zeoliticimidazolate framework), which has received great attention from researchers due to their physical and chemical characteristics such as high porosity, large surface area, low density, etc. Although ZIFs have a wide spectrum of applications in chemistry as catalysts and adsorptive materials, the chemical stability in solution of these materials is still little explored in the literature, limiting their potential in technological applications and industrial processes. Within the above, this work focuses on investigating the stability of ZIF-67 (cobalt (II) 2-methylimidazolate) in water and some organic solvents (methanol, ethanol, ethyl acetate, tetrahydrofuran, acetonitrile and N, N-dimethylformamide). The stability of these solvents as a function of time was also investigated, using infrared absorption spectroscopy as an analysis tool. As a result, we can see the high chemical stability of ZIF-67, which maintained its structure preserved in the exposure of the vast majority of organic solvents, proving inefficient in only two cases (water and tetrahydrofuran), showing a strong sign of degradation due to the sudden change in color. The ZIF-67 also showed chemical stability due to the exposure time of the solvent, with no changes in its infrared spectrum.