نشریه پژوهش های شیمیایی و نانو مواد
پیاپی 4 (زمستان 1401)

In this contribution, magnesium-based metal-organic frameworks (average size, 430 nm) were synthesized by a simple, low-cost, and high-efficient method utilizing different coordination solvents. The as-synthesized frameworks were then characterized by several characterization methods. The formation of metal-organic framework(MOF( coordination bindings was confirmed by FT-IR, EDX, UV-Vis, and SEM analyses. The organic content of the as-prepared MOFs was quantified by elemental analysis. The results showed that the coordination yield in protic solvents is higher than that of the aprotic solvents. In contrast, the organic content of the MOFs prepared in aprotic media was found to be more than that of the protic solvent due to the competitive role of aprotic solvents in the coordination process. The effect of coordination solvent on the biocompatibility of as-synthesized MOFs was also investigated using the standard protein absorption-desorption and hemolysis analysis. The protein adsorption results showed that the as-synthesized MOFs with protic solvents absorbed about 0.02 μg μg-1, which is 17.5-fold lower than that of the aprotic solvents. The hemolysis ratio of the synthesized sample in protic solvent was calculated at about 0.3%, which is 5 times lower than the hemolysis ratio of the synthetic sample in aprotic media, indicating their high erythrocyte compatibility. These findings reveal that the biocompatibility of magnesium-based metal-organic frameworks is significantly affected by the coordination solvent. The Authors strongly recommend using the results of this contribution for the synthesis of biocompatible carriers for drug and enzyme immobilization aims.

Cobalt coatings are considered a suitable alternative to chromium coatings due to their desirable properties and environmental compatibility. In this study, by adding phosphorus as an alloying element and reinforcing nanoparticles of ZrO2 and CeO2 to the cobalt coating matrix, amorphous Co-P-ZrO2-CeO2 and Co-P coatings were produced on a ST37 steel substrate using electrochemical deposition. The effect of current density on the morphology of the coatings was investigated by scanning electron microscopy (SEM), and the weight percentages of elements present in the coatings were analyzed using EDS analysis. Microhardness and corrosion resistance were also examined. The addition of reinforcing nanoparticles to the cobalt-phosphorus alloy matrix increased the hardness of the nanocomposite coatings. It should be noted that increasing the current density up to an optimal level increases the hardness, and then decreases it. The results of the Tafel and EIS analyses on the nanocomposite coatings indicate an increase in corrosion resistance with an enhancement in current density up to 100 mA/cm2 for both alloy and nanocomposite samples, which is due to an increase in the weight percentage of phosphorus and the formation of a surface protective layer. In addition, the presence of reinforcing nanoparticles in the matrix prevents corrosive medium from reaching the coating surface, improving its corrosion resistance.

This paper investigates the influence of acetaldehyde molecule adsorption on the structural and electronic properties of the SiC2 monolayer using density functional theory. For this purpose, different adsorption sites on the monolayer were investigated and the most stable structure was reported based on the adsorption energy. The results showed that the acetaldehyde molecule is physically adsorbed on SiC2 with an energy of about 0.310 eV. Comparing the band structure and density of states of SiC2 before and after the adsorption of acetaldehyde molecule showed that the energy gap and the distance between the Fermi level and the conduction band after acetaldehyde adsorption increase by 0.008 eV and 0.006 eV, respectively, which can cause a decrease in electrical conductivity. Based on the calculations, SiC2 can be used as an acetaldehyde gas sensor based on conductivity and, reaction heat change, or as an absorbent surface in piezoelectric gas sensors.

A very challenging concern of researchers in the last century has always been the production of chemicals at the nanometer scale, and at the same time, chemists have tried to understand how basic chemical principles change when systems are confined to nanoscale spaces. A long-pursued goal in nanoscience is to capture the essence of structures and functions of complex biological systems, as epitomised by cells, by creating artificial nanostructures in a rational manner. For this purpose, different strategies have been proposed and experimentally investigated. In the meantime, nanoreactors have been proposed as an emerging phenomenon and a new practical and scientific strategy for the production of nanomaterials. Nanoreactors change the basic chemical nature of molecules and moieties within them, and alter how they behave in chemical reactions. In fact, nanoreactors are very small chambers of nanometer size that protect the catalysts or the drug that is placed as a guest inside the nanoreactor structure from environmental influences, and they enclose reactants and catalysts in a small space for a long time, and as a result, they show great potential for improving chemical processes.The important point is that in addition to performing a wide range of chemical reactions, the space inside nanoreactors is a suitable environment for the production of various nanostructures. In this article, nanoreactors and some of their applications are briefly introduced.