Experimental and Theoretical Study For Removal of Trimethoprim (TMP) From Wastewater Using Organically Modified Silica With Pyrazole-3-Carbaldehyde Bridged To Copper Ions

BackgroundHuman and veterinary antibiotics are typically discharged as parent chemicals in urine or feces and are known to be released into the environment via wastewater treatment plants (WWTPs). Several research investigations have recently been conducted on the removal and bioremediation of pharmaceutical and personal care products (PPCPs) disposed in wastewater. ResultsSiNP-Cu, a chelating matrix, was produced by delaying and slowing 1.5-dimethyl-1H-pyrazole-3-carbaldehyde on silica gel from functionalized with 3-aminopropyltrimethoxysilane. The prepared sorbent material was characterized using several techniques including BET surface area, FT-IR spectroscopy, Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), and nitrogen adsorption-desorption isotherm. The pseudo-second-order model provided the best correlation due to the big match between the experimental and theoretical of different adsorption coefficients. The Langmuir and Freundlich adsorption models were used and the study showed better match with Fruendlich model. The removal capacity was depending on pH and increased by increasing pH The adsorbent demonstrated a high percentage removal of TMP, reaching more than 94 %. The sample was simply regenerated by soaking it for a few minutes in 1N HCl and drying it. The sorbent was repeated five times with no discernible decrease in removal capacity. Thermodynamic study also showed endothermic, increasing randomness and not spontaneous in nature. The findings of the DFT B3LYP/6-31+g (d,p) local reactivity descriptors revealed that nitrogen atoms and p-electrons of the benzene and pyrimidine rings in the TMP are responsible for the adsorption process with the SiNP surface. The negative values of the adsorption energies obtained by molecular dynamic simulation indicated the spontaneity of the adsorption process. ConclusionThe global reactivity indics prove that TMP is stable and it can be removed from wastewater using SiNP surface. The results of the local reactivity indices concluded that the active centers for the adsorption process are the nitrogen atoms and the p-electrons of the pyrimidine and benzene rings. Furthermore, the positive value of the maximum charge transfer number (DN) proves that TMP has a great tendency to donate electrons to SiNP surface during the process of adsorption.

Study of Reactivity and Molecular Stability by the Density Functional Theory Method on 2,3-Dihydro -1H-Perimidine: Comparative Analysis

Numerous studies have been carried out on the structure of 2,3-dihydro-1H-perimidine substituted as compounds with various biological activities. Researchers have found that these compounds exhibit characteristics potentially useful in medicinal chemistry research and have many therapeutic applications. In this work, we carried out a study using descriptors of the conceptual DFT in order to determine the atoms responsible for the chelation of certain metals (zinc, copper, iron ...) in order to propose new stable molecules complexed with these metals. Calculations were performed to determine the local reactivity of substituted 2,3-dihydro-1H-perimidine using Fukui functions by the Natural Population Analysis method. Overall parameters were also determined to predict the relative stability and reactivity of substituted 2,3-dihydro-1H-perimidine. This work was carried out at the calculation level B3LYP / 6-311G (d, p). Compound 2 with an energy difference from the frontier orbitals of ΔEgap = 4.031 eV is the most polarizable. Also, the study of frontier orbitals locates HOMO on the function of substituted 2,3-dihydro-1H-perimidine. Analysis of local reactivity indices as well as of the dual descriptor revealed that nitrogen N17 and N19 are the most favorable sites for electrophilic attack.

Investigation of the reactivity properties of a thiourea derivative with anticancer activity by DFT, MD simulations

Spectroscopic analysis of 1-(2-fluorophenyl)-3-[3-(trifluoromethyl)phenyl]thiourea (FPTT) is reported. Experimental and theoretical analysis of FPTT, with Molecular Dynamics (MD) simulations, are reported for finding different parameters like: identification of suitable excipients, interactions with water, and sensitivity towards autoxidation. Molecular dynamics and docking show that FPTT can act as a potential inhibitor for new drug. Additionally, local reactivity, interactivity with water, and compatibility of FPTT molecule with frequently used excipients have been studied by combined application of density functional theory (DFT) and MD simulations. Analysis of local reactivity has been performed based on selected fundamental quantum-molecular descriptors, while interactivity with water was studied by calculations of radial distribution functions (RDFs). Compatibility with excipients has been assessed through calculations of solubility parameters, applying MD simulations.

Understanding the Chemical Reactivity of Dihydroxyfumaric Acid and its Derivatives through Conceptual DFT

The chemical reactivity descriptors have been calculated through Molecular Electron Density Theory encompassing Conceptual DFT. The validity of �Koopmans� theorem in DFT� (KID) has been assessed by a comparison between the global descriptors (electronegativity, total hardness, and global electrophilicity) calculated through vertical energy values and those arising from the HOMO and LUMO values. These results suggest that the KID procedure is valid and may be used, in conjunction with the B3LYP/3-611G(d, p) level of theory in further studies of related compounds in the aqueous medium. The active sites for nucleophilic and electrophilic attacks have been identified and verified using the local reactivity descriptors: the dual descriptor, the electrophilic and nucleophilic Parr functions, the local reactivity difference index Rk and MEP maps. Obtained results suggest that the antioxidant/antiradical power of investigated compounds may be explained by the highest ambiphilic activation of the oxygen atoms of the hydroxyl groups in the ene-diol moiety.