Average Local Ionization Energy Research Articles

First oxidative coupling of cyclazine heterocycle via regioselective dimerization of 1,2-dicarbomethoxy-3-phenylcycl[3.2.2]azine: synthesis, theoretical aspects and physicochemical studies

The first covalently linked dimer has been prepared for cyclazine systems by regioselective oxidative homocoupling of 1,2-dicarbomethoxy-3-phenylcycl[3.2.2]azine. The regioselectivity of this reaction at 4-position, having been confirmed by X-ray diffraction analysis and NMR spectroscopy, has been also reliably predicted within the model of average local ionization energy on the molecular surface of the starting monomer at the BP86/def2-TZVP level of theory. Due to the planar π-π interaction of the cycl[3.2.2]azine subunits, the dimer is a green fluorophore (λem = 527 nm, toluene), characterized by a bathochromic shift of the main bands in the UV-vis and fluorescence spectra relative to the monomer by 41 and 71 nm, respectively. Furthermore, the dimer demonstrates an increased fluorescence quantum yield relative to the monomer (55% vs. 35% in toluene), and according to the data of X-ray diffraction analysis, DFT calculations and variable temperature 1D and 2D 1H NMR spectroscopy, is characterized by hindered rotation of the S1-state-involved cycl[3.2.2]azine cores along the C4-C4' bond axis. Such prerequisites determine good application potential of the 4-4' coupled cycl[3.2.2]azine derivatives as turn-on fluorescent, i.e. fluorogenic probes for advanced bioimaging in living systems. Finally, unlike the monomer, the dimer shows reversibility of both one- and two-electron reduction and oxidation processes, and therefore can become the basis of both n- and p-type semiconductors.

In-silico Study of Molecular Docking and Dynamics Simulations for N-Substituted Thiazolidinones Derived from (R)-Carvone Targeting PPAR-γ Protein: Synthesis and Characterization

In this article, we have selected the monoterpene (R)-carvone combined with thiazolidinone as scaffold. Moreover, this study details the synthesis, characterization, and theoretical analysis of novel (R)-Carvone-thiazolidinone-N-substituted derivatives, sourced from natural (R)-Carvone. The compounds were identified using HRMS, and 1H- and 13C-NMR spectral data. A theoretical analysis provided insights into the stability observed experimentally. The local electronic properties and topological features of two compounds 3 and d were studied using the Multiwfn tool and CrystalExplorer software. Specifically, the electron localization function, localized orbital locator and average local ionization energy were mapped to explore electron distribution, while interaction region indicator was used to analyze intermolecular interactions. An in silico docking study was conducted on the PPAR-γ protein to evaluate the binding affinity and interactions. Furthermore, a 200 ns molecular dynamics simulation was performed to confirm the stability of the compounds within the PPAR-γ protein’s binding site. The results indicated consistent stability for all three compounds under dynamic conditions. Lastly, in silico evaluations of drug-likeness and toxicity prediction showed that all compounds adhere to the criteria of both Lipinski’s Rule of Five and Jorgensen’s Rule of Three, confirming their potential as drug candidates.

A comparative theoretical study on the structural, spectral, microtopology exploration (ELF, RDG, IRI, TDM), NBO and nonlinear optical properties of Red170 from different solvents and substituents

The effect of solvents and substituents on the C.I. Pigment PR170, the best known member of the naphthol red family, is investigated. Both PR170 and its alkoxy derivatives were analyzed using FTIR, 1H NMR and UV–Vis spectroscopy. The study included the evaluation of the average local ionization energy (ALIE), MEP, HOMO-LUMO analysis. The nature of intra- and intermolecular contacts in the crystal structure was also investigated using crystal packing and Hirshfeld surface analysis. Covalent and non-covalent interactions in PR170 were comprehensively described by IRI, RDG and ELF. In addition, Natural Bonding Orbital (NBO) and Fukui function calculations were performed. An analysis of the UV–Vis electronic transitions for different solvents was carried out, providing insight into the charge transfer processes within both PR170 and its derivatives. In particular, the research indicated a CT-type excitation at the S2 level during the hole-electron transfer analysis. The NLO results showed that PR170 is a promising candidate for nonlinear optical materials.

Research on the molecular structure, solvent effects, quantum computing, topology, and biological aspects of 4-phenylcoumarin-7-yl-methacrylate as an anticancer agent

The objective of this research is to conduct both experimental and theoretical analyses on the synthesis and characterization of a new coumarin derivative known as 4-phenylcoumarin-7-yl-methacrylate (PCMA). To accomplish this, several methods including 1H-NMR, FT-IR, and UV-visible spectroscopy were employed, and atomic charges and bond parameters were calculated using the DFT-B3LYP/6-311G++(d,p) basis set. Additionally, topological properties such as Electron Localized Function, Localized Orbital Locator and Non-Covalent interactions (RDG-NCI) were thoroughly examined. The TD-DFT approach was used to calculate the UV-Vis absorption technique in various solvent media, and the Light Harvesting Efficiency was also investigated. An analysis of Frontier Molecular Orbitals (FMO), Molecular Electrostatic Potential (MEP), and Average Local Ionization Energy (ALIE) simulations were conducted to identify the optimal sites for both electrophilic and nucleophilic attacks. Nonlinear Optical (NLO) behavior was also examined by determining the dipole moment (μ), the linear polarizability (α), first hyperpolarizability (β) and second hyperpolarizability (γ) through the use of the same basis set. To better understand molecular stability and interactions, Natural Bond Orbital (NBO) analysis was performed, providing insights into hyperconjugative interactions, charge delocalization, and electron density (ED) among the molecular components. Electron-hole and TDM analysis were also conducted to investigate the various types of electron-excited states. This research will additionally explore the drug-likeness and docking potential of PCMA, with the goal of determining its suitability as a potential candidate for cancer treatment. This comprehensive study offers valuable insights into the structural, electronic, and biological properties of 4-phenylcoumarin-7-yl-methacrylate (PCMA).

Weak interaction induced selective separation of V/Mo/Co from spent hydrodesulfurization catalyst leaching solution: Mechanism and strategy

Spent hydrodesulfurization catalysts contain more than 10 ∼ 25 wt% V, Mo and Co, which are not only hazardous materials, but also can be considered as valuable secondary resources. The complete separation of these complex critical metals by solvent extraction still needs to be improved. Here, a selective extraction route for the separation of V/Mo/Co is proposed based on the weak interaction differences between extractants and metal, which is realized by theoretical calculation and experimental verification. This process does not require pretreatment of N1923 and Cyanex272 (C272), thus reduced the consume of acid and base as well as generation of waste water. With the preliminary results of V/Mo, Co/Mo, and V/Co separation, the weak interaction between extractants and metal molecules was revealed by quantum chemical calculations quantitatively. The molecular charge distribution, surface electrostatic potential distribution (ESP) and the average local ionization energy (ALIE) shows the priority reactivity of the metal molecules as: H6V10O28 > H2Mo4O13 > H4V4O12 > H3VO4 > H2MoO4. The independent gradient model based on Hirshfeld partition (IGMH) show differences in the weak interaction forces as: N1923-V>C272-Mo > C272-V>N1923-Mo > C272-Co. The selective separation process of V/Mo/Co was designed with the guide of above results. The combined recovery of the three metals V, Mo and Co amounted to 83.88 %, 87.08 %, and 99.01 %, respectively. The whole route reduces 3.92 t sulfuric acid and 7.83 t sodium hydroxide per solid, and reduces 1.99 t carbon emissions compared to the conventional route.

Theoretical analysis of naproxen reaction with sulfate and hydroxyl radicals in the aqueous phase: Investigating reactive sites and reaction kinetics

In this study, we have utilized theoretical calculations to predict the reaction active sites of naproxen when reacting with radicals and to further study the thermodynamics and kinetics of the reactions with ·OH and SO4−·. The evidence, derived from the average local ionization energy and electrostatic potential, points to the naphthalene ring as the preferred site of attack, especially for the C2, C6, C9, and C10 sites. The changes in Gibbs free energy and enthalpy of the reactions initiated by ·OH and SO4−· ranged between −19.6 kcal/mol - 26.3 kcal/mol and −22.3 kcal/mol −18.5 kcal/mol, respectively. More in-depth investigation revealed that RA2 pathway for ·OH exhibited the lowest free energy of activation, suggesting this reaction is more inclined to proceed. The second-order rate constant results indicate the ·OH attacking reaction is faster than reactions initiated by SO4·-, yet controlled by diffusion. The consistency between theoretical findings and experimental data underscores the validity of this computational method for our study.

Synthesis, experimental and theoretical spectra, electronic and medicinal properties of 3-(3-(4-chlorophenyl)-1-phenyl-1H-pyrazol-4-yl)-5-ethoxy-4H-1,2,4-triazole

In this work, 3-(3-(4-Chlorophenyl)-1-phenyl-1H-pyrazol-4-yl)-5-ethoxy-4H-1,2,4-triazole compound has been synthesized and experimentally (FT-IR and 1H and 13CNMR) evaluated. .Density Functional Theory (DFT) is applied to investigate solvent solutes using a variety of solvents. The computed frequencies have been scaled. In global reactive parameters solvents significantly altered the molecule's characteristics behaviour, gas and water has high electrophilicity index which trigger its biological activity. The description focuses on how electron fragments influence the stimulation of electron states. From p*(C23-C24) to p*(C20-C25) and p*(C21-C22), the energy stabilised is 246.13 and 170.28 kcal/mol it is a significant stabilizing energy. Molecular Electrostatic Potential (MEP) shows that vast majority of each positive domain is near hydrogen atoms; almost all of the negative domain is close to NN atoms in both the gas and solvent phases. TDM (Transition Density Matrices) analysis presents graphical representations that depict the ability to transmit charges. Average local Ionization Energy (ALIE) scrutiny uses the colour blue to symbolize the stable sigma bonds, commonly linked to hydrogen atoms that generate protons. The choice of solvent significantly impacts its overall characteristics and chemical activity. In the topological aspect (with solvents), the most fragile acquaintances, binding zones, or the density of electron variations were all detected. Furthermore, a significant relationship exists between the electrical features of solvents and their polarization. According to Lipinski's rule of five, using a pill-sized quantity of such chemicals is generally safe. We also examined the molecule's biological activity by docking an adenogenic receptor. The anti-adenosine replicating protein (1Y56) binds most strongly (-7.10 kcal/mol) and interacts with other molecules in the most non-covalent ways.

Molecular simulation-based assessing of a novel metal-organic framework modified with alginate and chitosan biopolymers for anionic reactive black 5 and cationic crystal violet pollutants capture

This study employed molecular simulations to develop efficient and environmentally friendly adsorbents for removing two common dye pollutants, crystal violet (CRVT) and reactive black 5 (RBC5). The investigated adsorbents are based on biodegradable polymers alginate (ALG) and chitosan (CHAN) functionalized with carboxyl acid groups (CA) on a UIO-66 metal–organic framework (MOF). Density functional theory (DFT) analyses such as electrostatics potential (ESP), Average local ionization energy (ALIE) analysis, COSMO-RS (Conductor-like Screening Model for Real Solvents) analysis and the density of states (DOS) were performed to investigate the structures of the pollutants and adsorbents. Physical and chemical properties of the adsorbents, including density, Hamiltonian energy (HAE), the radius of gyration (ROG), and the stress autocorrelation function (SACF) were also examined. Additionally, molecular dynamics (MD) and Monte Carlo (MC) simulations were employed to study the adsorption of CRVT and RBC5 onto CA/UIO-66, CA/UIO-66/ALG, and CA/UIO-66/CHAN adsorbents. The results demonstrated that functionalizing CA/UIO-66 with CHAN and ALG significantly enhances the adsorption capacity for both CRVT and RBC5. The modified adsorbent demonstrated significantly higher affinity towards RBC5 compared to CRVT, as evidenced by the adsorption energies of −1.11 × 104 kcal/mol for CA/UIO-66-CHAN-W-CRVT and −1.36 × 107 kcal/mol for CA/UIO-66-CHAN-W-RBC5. This research highlights the potential of CHAN- and ALG-functionalized CA/UIO-66-based adsorbents as promising alternatives to current wastewater treatment methods. These adsorbents are efficient, biodegradable, and environmentally friendly, offering remarkable potential for removing dye pollutants from industrial and domestic wastewater.

Deciphering the interactions between altertoxins and glutenin based on molecular dynamic simulation: inspiration from detection.

Mycotoxin contamination of food has been gaining increasing attention. Hidden mycotoxins that interact with biological macromolecules in food could make the detection of mycotoxins less accurate, potentially leading to the underestimation of the total exposure risk. Interactions of the mycotoxins alternariol (AOH) and alternariol monomethyl ether (AME) with high-molecular glutenin were explored in this study. The recovery rates of AOH and AME (1, 2, and 10 μg kg-1) in three types of grains (rice, corn, and wheat) were relatively low. Molecular dynamics (MD) simulations indicated that AOH and AME bound to glutenin spontaneously. Hydrogen bonds and π-π stacking were the primary interaction forces at the binding sites. Alternariol with one additional hydroxyl group exhibited stronger binding affinity to glutenin than AME when analyzing average local ionization energy. The average interaction energy between AOH and glutenin was -80.68 KJ mol-1, whereas that of AME was -67.11 KJ mol-1. This study revealed the mechanisms of the interactions between AOH (or AME) and high-molecular glutenin using MD and molecular docking. This could be useful in the development of effective methods to detect pollution levels. These results could also play an important role in the evaluation of the toxicological properties of bound altertoxins. © 2024 Society of Chemical Industry.

Proton-Coupled Electron Transfer and Hydrogen Tunneling in Olive Oil Phenol Reactions.

Olive oil phenols are recognized as molecules with numerous positive health effects, many of which rely on their antioxidative activity, i.e., the ability to transfer hydrogen to radicals. Proton-coupled electron transfer reactions and hydrogen tunneling are ubiquitous in biological systems. Reactions of olive oil phenols, hydroxytyrosol, tyrosol, oleuropein, oleacein, oleocanthal, homovanillyl alcohol, vanillin, and a few phenolic acids with a DPPH• (2,2-diphenyl-1-picrylhydrazyl) radical in a 1,4-dioxane:water = 95:5 or 99:1 v/v solvent mixture were studied through an experimental kinetic analysis and computational chemistry calculations. The highest rate constants corresponding to the highest antioxidative activity are obtained for the ortho-diphenols hydroxytyrosol, oleuropein, and oleacein. The experimentally determined kinetic isotope effects (KIEs) for hydroxytyrosol, homovanillyl alcohol, and caffeic acid reactions are 16.0, 15.4, and 16.7, respectively. Based on these KIEs, thermodynamic activation parameters, and an intrinsic bond orbital (IBO) analysis along the IRC path calculations, we propose a proton-coupled electron transfer mechanism. The average local ionization energy and electron donor Fukui function obtained for the phenolic compounds show that the most reactive electron-donating sites are associated with π electrons above and below the aromatic ring, in support of the IBO analysis and proposed PCET reaction mechanism. Large KIEs and isotopic values of Arrhenius pre-exponential factor AH/AD determined for the hydroxytyrosol, homovanillyl alcohol, and caffeic acid reactions of 0.6, 1.3, and 0.3, respectively, reveal the involvement of hydrogen tunneling in the process.

Effect of pH on the ozonolysis degradation of p-nitrophenol in aquatic environment and the synergistic effect of hydroxy radical.

Density functional theory (DFT) was employed to elucidate the mechanisms for ozonolysis reaction of p-nitrophenol (PNP) and its anion form aPNP. Thermodynamic data, coupled with Average Local Ionization Energies (ALIE) analysis, reveal that the ortho-positions of the OH/O- groups are the most favorable reaction sites. Moreover, rate constant calculations demonstrate that the O3 attack on the C2-C3 bond is the predominant process in the reaction between neutral PNP and O3. For the aPNP + O3 reaction, the most favorable pathways involve O3 attacking the C1-C2 and C6-C1 bonds. The rate constant for PNP ozonolysis positively correlates with pH, ranging from 5.47 × 108 to 2.86 × 109M-1s-1 in the natural aquatic environment. In addition, the formation of hydroxyl radicals in the ozonation process of PNP and the mechanisms of its synergistic reaction of PNP with ozone were investigated. Furthermore, the ozonation and hydroxylation processes involving the intermediate OH-derivatives were both thermodynamically and kinetic analyzed, which illustrate that OH radicals could promote the elimination of PNP. Finally, the toxic of PNP and the main products for fish, daphnia, green algae and rat were assessed. The findings reveal that certain intermediates possess greater toxicity than the original reactant. Consequently, the potential health risks these compounds pose to organisms warrant serious consideration.

Biocompatible citrate-cysteine complexes of manganese as effective antioxidants: Experimental and computational studies

Many clinical studies have evaluated the ability of sulfur-containing antioxidants to prevent oxidative stress, a major cause of cancer, Parkinson's, and Alzheimer's disease. Cysteine complexes of manganese modified with citric acid were synthesized by a one-pot procedure in two molar ratios and at two different temperatures (90°C, 140°C). The synthesized complexes were studied using FT-IR, UV-Vis, NMR, and EDX. At the lower temperature, a hydrogel was formed, and a thiazolopyridine ring was formed at a temperature of 140°C which was complexed with manganese. Infrared and electronic absorption spectroscopy confirmed that manganese binding occurred via the oxygen atoms of COO. The complexes also exhibited strong fluorescence with excitation/emission peak wavelengths of 350/418 nm. The synthesized compounds showed efficient activity for superoxide scavenging (> 70%), which was evaluated by a pyrogallol autoxidation method. MTT assay studies confirmed the noncytotoxic nature of all the prepared samples. The Gaussian 09 program was used to optimize the structural configurations of the ligands and complexes based on DFT by the B3LYP/6-31+G(d) basis set. To evaluate the softness of both the ligand and the complex, an investigation of the HOMO-LUMO gaps was carried out. In addition, UV-vis spectra of Mn complexes obtained from the time-dependent DFT calculations show a strong peak in the range of 380-390 nm, which is in good agreement with our experimental findings. The results revealed that the oxygen atoms of citrate and cysteine are the most potential sites to interact with the Mn atom. Besides, the calculated average local ionization energies showed that the Mn atom is the most energetically favored and vulnerable site to an electrophilic or free radical attack.

Biginelli dihydropyrimidines carrying azole rings: Synthesis, computational studies, and evaluation of alpha‐glucosidase inhibitory and antimicrobial activities

In the current study, we designed three novel compounds by merging two valuable nitrogen-containing pharmacophores, namely dihydropyrimidine (DHPM) and azole, within a single molecule. To obtain the target molecules, azole-linked benzaldehydes were initially synthesized via nucleophilic aromatic substitution reaction between 4-fluorobenzaldehyde and pyrazole, imidazole, or 1,2,4-triazole. Afterward, Biginelli reaction was applied to yield azole-carrying DHPMs. Following structural confirmation, the obtained compounds were tested for their alpha (α)-glucosidase inhibitory and antimicrobial activities. According to the biological data, DHPM-P and DHPM-T showed strong inhibition values whereas DHPM-I failed to effectively inhibit the α-glucosidase enzyme. This situation was explained by molecular docking studies of all compounds into the binding site of alpha-glucosidase. The title compounds also presented moderate antibacterial and antifungal activities. Computational methods based on density functional tight binding (DFTB) and density functional theory (DFT) calculations, along with molecular dynamics (MD) simulations were used to analyze the reactive properties of the compounds. A combination of DFTB and DFT calculations was applied to obtain the lowest energy conformations of the molecules. Further computational analysis included calculations of local reactivity descriptors, such as molecular electrostatic potential and average local ionization energy, by applying DFT calculations. DFT calculations were also used to study intramolecular non-covalent interactions. MD simulations were employed to understand how the title molecules behave in water and to obtain their solubility parameters.

Boiling, critical, and freezing temperatures in light of molecular descriptors: correlation and causation.

In the pursuit of tracking some physicochemical properties of fluids down to the molecular level, ab initio molecular surface analyses were performed on 169 molecules. This included electrostatic potential (EP), average local ionization energy (ALIE), and electron localization function (ELF) mapped onto an electron density isosurface value of 0.001 au. Using stepwise linear regression (SLR) analysis, it was found that besides the well-studied EP, ALIE and ELF played important roles in determining the normal boiling and freezing points and critical temperatures of fluids. Apparently, the ALIE and ELF were relevant to the attractive polarization forces and repulsive Pauli forces, respectively, between molecules. To further demonstrate and rationalize this assumption, a localized molecular orbital energy decomposition analysis (LMO-EDA) was carried out. In the LMO-EDA analysis, the complexes of the helium atom, He, and ClCl, ClBr, ClI, OCO, OCS, OCSe, and CO/OC molecules were investigated, where the helium atom faced different molecular sites in each molecule. Fortunately, the results showed that lower the ALIE value on a molecular site, the stronger (i.e., more attractive) the polarization interaction energy. The results also indicated that higher the ELF value on a molecular site, the stronger (i.e., more repulsive) the Pauli interaction. The work is aimed to present novel molecular-based rationales to physical chemists, chemical engineers, and materials scientists.

Unveiling the Quantitative Relationships between Electron Distribution and Steric Hindrance of Organic Amines and Their Reaction Rates with Carbonyl Sulfur: A Theoretical Calculation Investigation.

The removal of carbonyl sulfide (COS) commonly contained in natural gas is of great significance but still very challenging via a widely employed absorption process due to its low reactivity and solubility in various commercial solvents. Artificial intelligence (AI) is playing an increasingly important role in the exploration of desulfurization solvents. However, practically feasible AI models still lack a thorough understanding of the reaction mechanisms. Machine learning (ML) models established on chemical mechanisms exhibit enhanced chemical interpretability and prediction performance. In this study, we constructed a series of solvent molecules with varying functional groups, including linear aliphatic amines, cyclic aliphatic amines, and aromatic amines and proposed a three-step reaction pathway to dissect the effects of charge and steric hindrance of different substituents on their reaction rates with COS. Chemical descriptors, based on electrostatic potential (ESP), average local ionization energy (ALIE) theory, Hirshfeld charges, and Fukui functions, were used to correlate and predict the electrophilic reactivity of amine groups with COS. Substituents influence the reaction rate by changing the attraction interaction of amine groups to COS molecules and the electron rearrangement in the electrophilic reaction. Furthermore, they have more pronounced steric effects on the reaction rate in the linear amines. The descriptors N_ALIE and q(N) were found to be crucial in predicting the reactivity of amine groups with COS. Present study provides a comprehensive understanding of the reaction mechanisms of COS with amine compounds, offers specific chemical principles for the development of chemistry-driven ML models, sheds light on other types of electrophilic reactions occurring on amine and phosphine groups, and guides the development of chemical solvents in gas absorption processes.

Comprehensive solubility study and inter-molecular interactions on fenbendazole dissolved in some aqueous aprotic and protic co-solvent solutions

The isothermal shake-flask saturation method was used to experimentally determine the mole-fraction solubility of fenbendazole in three aqueous co-solvent blends of 1,4-dioxane/acetone/NMP encompassing the range of 283.15 to 328.15 K. The solubility of fenbendazole in various blended solvents ranks NMP + water (4.852 × 10−2) > 1,4-dioxane + water (14.81 × 10−4) > acetone + water (2.285 × 10−4) with composition of 1,4-dioxane (acetone or NMP) of 1 at 298.15 K. The solubility data rises monotonically with 1,4-dioxane/acetone/NMP concentration at the same temperature. X-ray power diffraction images show that no solvate production or crystal transition appeared throughout the studies. The solubility to solvent composition and temperature was satisfactorily associated by the modified van't Hoff-Jouyban-Acree, quantitative structure–property relationship, and Jouyban-Acree models with relative average deviations of no higher than 7.05 % and root-mean-square deviation of no higher than 1.225 × 10−3. In addition, the 1,4-dioxane/acetone/NMP + water blends studied in this paper and the methanol/ethanol/EG/DMF + water blends previously reported both used the extended Hildebrand solubility approach to quantitatively describe the solubility behavior at 298.15 K. The average relative deviations were kept under 4.06 % on both cases. As stated by the examination of the linear solvation energy relationship, the solubility parameter and dipolarity-polarizability of solutions have a significant influence on the solubility variation. The effective method of inverse Kirkwood-Buff integrals was used to investigate the preferred solvation of fenbendazole at 298.15 K. In blends with intermediate and rich ethanol/DMF/1,4-dioxane/acetone/NMP composition areas, the preferred solvation parameters of ethanol/DMF/1,4-dioxane/acetone/NMP displayed positive values, indicating the preferential solvation of fenbendazole by the co-solvents. Thermodynamic examination of the entropy-enthalpy compensation and dissolution parameters for fenbendazole dissolving in blends led to the identification of an enthalpy and/or entropy-driven mechanism as well as an endothermic process. Moreover, the average local ionization energy and electrostatic potential of molecular surface were utilized as effective instruments to demonstrate the microscopic electrostatic properties of acidity and basicity, respectively. The fenbendazole molecule's groups of –N in the five-membered ring and –NH in the straight chain serve as the main targets for electrophilic and nucleophilic assault. The weak interactions between fenbendazole and several solvents were shown using an independent gradient model based on Hirshfeld partition analysis.

Assembling Nitroamino and Amino Groups on a Pyrazolyl-1,3,4-Oxadiazole Framework for the Construction of High-Performance and Insensitive Energetic Materials

AbstractThe introduction of nitroamino groups onto a nitrogen-rich heterocyclic skeleton is an efficient method for constructing high-performance energetic compounds. In this work, the nitroamino-functionalized compound 4-(5-amino-1,3,4-oxadiazol-2-yl)-N,N′-dinitro-1H-pyrazole-3,5-diamine was synthesized in yields of up to 83%. In addition, its energetic salts were also prepared. All these compounds were characterized by NMR and IR spectroscopy and, in two cases, by single-crystal X-ray diffraction. In addition, the difference in the reactivities of the three amino groups on the pyrazolyloxadiazole system was analyzed by an average local ionization energy analysis. The hydrazinium salt of the diamine exhibits promising detonation properties and good molecular stability, suggesting it has good application potential. Compared with previous works, this strategy gives an improved isolated yield and provides a promising method for the construction of nitroamino-functionalized 1,3,4-oxadiazole derivatives.

Unveiling the potential and mechanisms of 3,3′-bicarbazole-based quaternary ammonium salts as levelers

It is important to introduce an effective leveler into electroplating bath to meet the desired requirement in the electronic industry. This work explored the impact of larger backbone structures of four 3,3′-bicarbazole quaternary ammonium salts on the performance of promising levelers in light of the ambiguous mechanism of action. For the first time, these four compounds have been functionalized and identified as promising levelers for copper electrodeposition in through holes. Electrochemical measurements, theoretical calculations, and dynamics simulations collectively revealed that among these levelers, BCz-BPD exhibits the tendency of optimal adsorption on the cathode with the strongest inhibition of copper deposition. Chronoamperometry tests were carried out to analyze the copper nucleation model during electroplating. By measuring the electrostatic potential, average local ionization energy, and planarity, the leveling mechanism of BCz-BPD leveler was analyzed. In order to confirm the high through-hole filling and excellent leveling performance of BCz-BPD in actual PCB plating, TP value measurement, SEM, and XRD tests were carried out sequentially. In addition, galvanostatic measurements were performed to study the interaction of BCz-BPD leveler with other kinds of additives.

Connection between nuclear and electronic Fukui functions beyond frontier molecular orbitals.

Based on the relationship between average local ionization energy Ī(r) and average local electron affinity Ā(r) with the electronic Fukui functions, i.e., f-(r) and f+(r), respectively, in this paper, we establish a connection between nuclear and electronic Fukui functions beyond frontier molecular orbitals. As a consequence of this connection, we obtain expressions of average nuclear Fukui functions interpreted as a variation of average nucleophilicity or electrophilicity (weighted by the electronic orbital Fukui functions) with respect to nuclear displacements, which goes beyond the highest occupied molecular orbital/or lowest unoccupied molecular orbital consideration. Furthermore, from this connection and considering the frontier molecular orbital approximation, we derive expressions of nuclear Fukui functions in terms of the atom-condensed electronic Fukui functions, which imply a locality in the chemical reactivity and could be used to study the variation of local nucleophilicity or electrophilicity with respect to nuclear displacements. Finally, this new way to interpret the nuclear Fukui function could be useful in the future to study the chemical reactivity related to molecular vibrations, internal rotations, bond dissociation, chemical reaction along the model of reaction coordinate, and so on.

Molecular Mechanisms Involved in the Chemical Instability of ONC201 and Methods to Counter Its Degradation in Solution.

Glioblastoma is one of the most common and aggressive forms of brain tumor, a rare disease for which there is a great need for innovative therapies. ONC201, a new drug substance, has been used in a compassionate treatment program where the choice of dosage form and regimen have yet to be justified. The prior knowledge needed to anticipate ONC201 stability problems has recently been partially addressed, by (i) showing that ONC201 is sensitive to light and oxidation and (ii) identifying the molecular structures of the main degradation products formed. The aim of the work presented here was to improve our understanding of the degradation pathways of ONC201 using data from ab initio calculations and experimental work to supplement the structural information we already published. The C-H bonds located αto the amine of the tetrahydropyridine group and those located alpha to the imine function of the dihydroimidazole group exhibit the lowest bond dissociation energies (BDEs) within the ONC201 molecule. Moreover, these values drop well below 90 kcal.mol-1 when ONC201 is in an excited state (S1; T1). The structures of the photoproducts we had previously identified are consistent with these data, showing that they would have resulted from radical processes following the abstraction of alpha hydrogens. Concerning ONC201's sensitivity to oxidation, the structures of the oxidation products matched the critical points revealed through mapped electrostatic potential (MEP) and average local ionization energy (ALIE). The data obtained from ab initio calculations and experimental work showed that the reactivity of ONC201 to light and oxidation conditions is highly dependent on pH. While an acidic environment (pH < 6) contributes to making ONC201 quantitatively more stable in solution in the face of oxidation and photo-oxidation, it nevertheless seems that certain chemical groups in the molecule are more exposed to nucleophilic attacks, which explains the variation observed in the profile of degradation products formed in the presence of certain antioxidants tested. This information is crucial to better understand the stability results in the presence of antioxidant agents and to determine the right conditions for them to act.