No abstract

Synthesis of coordination polymers based on magnesium(II) and benzene 1, 3, 5-tricarboxylic acid (H3BTC) with two different types of magnesium(II) salts precursors, namely MgCl2·6H2O and Mg(OAc)2·4H2O in ethanol under solvothermal condition was successfully carried out. The synthesized materials were characterized by several methods such as X-Ray Diffraction and FTIR spectroscopy, thermogravimetry and scanning electron microscopy (SEM). The synthesis results showed that the crystallization of the materials was highly influenced by the type of metal ion precursor Mg(II), in this case the anion. XRD analysis revealed that the use of MgCl2·6H2O salt tend to produce a coordination polymer [Mg3(BTC)2 (H2O)12] which called also as National Institute of Chemistry Slovenia-4 (NICS-4, CCDC 768993) with a 1-dimensional structure, while the use of Mg(OAc)2·4H2O salt produced 3-dimensional coordination polymer [Mg3(BTC)2] or well known as National Institute of Chemistry Slovenia-6 (NICS-6, CCDC 768995). NICS-4 and NICS-6 have thermal stability up to 530 ºC and 542 ºC based on the thermogravimetric analysis. A significant shift from absorption peak at 1721 to 1622 dan 1628 cm−1 correspond to the deprotonation of trimesic acid and coordinated to the Mg2+ cation. The coordination of Mg2+ with H2O molecules in NICS-4 is indicated by the presence of broad absorption peak at 3472 cm−1 which was not found in NICS-6. After exposed to the air, the structural dimension of NICS-6 could change due to the coordination with water molecules. SEM image exhibited that NICS-4 has flat-needle-like morphology with an average particle size of 12.42 ± 0.78μm, while NICS-6 has a hollow spherical morphology with an average particle size of 63.21 ± 0.12 μm.

This study aimed to synthesize a composite material consisting of metalorganic framework based magnesium(II) and benzene-1,3,5-tricarboxylic acid (H 3 BTC) and its modification using graphene oxide (GO) and Fe 3 O 4. The obtained material (i.e., [Mg 3 (BTC) 2 ]/GO/Fe 3 O 4) was studied as a matrix for the slow release of ibuprofen. [Mg 3 (BTC) 2 ]/GO/Fe 3 O 4 matrices were synthesized ex situ with the sonochemical method (material 1) and in situ with the solvothermal method (material 2). The obtained materials were completely characterized by X-ray diffraction and Fourier-transform infrared spectroscopy. Based on scanning electron microscopy imaging, the produced materials were spherical. The presence of GO and Fe 3 O 4 in material 1 and material 2 reduced the surface area, but it increased the adsorption capacity of ibuprofen up to 94.12%. The magnetic properties of materials 1 and 2 were observed using a vibrating sample magnetometer. These results demonstrate that modification of Fe 3 O 4 nanoparticles induces paramagnetic properties in both materials. The presence of this matrix material was able to release ibuprofen up to seven times slower at pH 5.0 and 12 times slower at pH 7.4. An increase in the pH lead to an increase in the concentration of ibuprofen released to 33.31% more than at pH 5.0.

The cover image is based on the Full Paper* The novel composite material MOF‐[Mg3(BTC)2]/GO/Fe3O4 and its use in slow‐release ibuprofen by Witri Wahyu Lestari** et al., https://doi.org/10.1002/aoc.5670.***