Electrostatic Potential Calculations Research Articles

A High-Performance Polyimide Composite Membrane with Flexible Polyphosphazene Derivatives for Vanadium Redox Flow Battery.

A sulfonated polyimide, S-F-abSPI, with alkyl sulfonic acid side chains, and a polyphosphonitrile derivative, poly[4-methoxyphenoxy (4-fluorophenoxy) phosphazene] (PFMPP), were designed and synthesized. Composite modification of the S-F-abSPI membrane was carried out using PFMPP, resulting in the preparation of composite membranes with different composite ratios, which were then subjected to performance testing and characterization. Experimental results revealed a significant enhancement in the proton conductivity of the S-F-abSPI membrane, reaching 0.116 S cm-1, slightly higher than that of the N212 membrane. The S-F-abSPI/1% PFMPP composite membrane exhibited the optimal comprehensive performance, with a surface resistance as low as 0.54 Ω cm2, comparable to that of the N212 membrane. At a high current density of 200 mA cm-2 during charge-discharge, the composite membrane achieved a voltage efficiency (VE) of 83.12% and an energy efficiency (EE) of 81.95%. Cycling tests over 200 cycles demonstrated the composite membrane's excellent long-term cycling stability. The alkyl sulfonic acid side chains enhanced the proton conductivity of the membrane, while electrostatic potential distribution calculations indicated strong interactions between PFMPP and the base membrane, enhancing the membrane's mechanical strength, reducing vanadium ion permeability, and improving chemical stability and vanadium ion selectivity. This composite membrane holds promise for high-performance VRFB applications.

Synthesis of novel isostere analogues of naphthyridines using CuI catalyst: DFT computations (FMO, MEP), molecular docking and ADME analysis

An approach towards the synthesis of novel isosteres of benzonaphthyridines and benzonaphthonaphthyridines from the condensation reaction between 4-chloro-2-methylquinolines/4-chloro-2-methylbenzo[h]quinoline and appropriate o-amino aromatic and heteroaromatic carboxylic acids by using solvent (ethanol)/solvent free (neat) condition to yield the intermediate followed by the cyclization with PPA. The intermediate yield has been slightly increased in neat (solvent-free) conditions compared to solvent conditions. Further, the target isosteres of benzonaphthyridines and benzonaphthonaphthyridines were achieved in the one-pot synthesis using a CuI catalyst with a higher yield than the stepwise method. Quantum chemical calculations of synthesized compounds are performed by using M06-2X with 6-311+G(d,p) basis set in water, DFT calculations of the molecular electrostatic potential (MEP), frontier molecular orbitals (FMOs), and the optimized geometry of the XRD values are compared with experimental values. All the synthesized novel isosteres molecules are investigated under molecular docking studies using MMP1 and MMP2 proteins, which showed all the molecules have the potential to heal pancreatic cancer. The most potent molecules among them are 3i and 3h due to their better docking scores. Furthermore, the molecules' pharmacokinetic (ADME) parameters have been observed to be effective in future biological evaluations of these compounds to be active.

Rich active sites ZIF-8 base on imidazole-based deep eutectic solvents for rapid adsorption of acid fuchsin and competitive adsorption

MimDES-ZIF-8 with rich active sites as positive charges and metal coordination sites were prepared based on imidazole based deep eutectic solvent (MimDES) using interface permeation method. 2-Methylimidazole (2-Mim) simultaneously acted as a hydrogen bond acceptor (HBA) in MimDES (hydrogen donner was 1,6-hexanediol) and an organic ligand in MimDES-ZIF-8, affecting the coordination of ZIF-8 during permeation. Four different zinc salt solutions (ZnCl2, Zn(NO3)2·6H2O, Zn(OAc)2·2H2O, ZnSO4·7H2O) were permeated into MimDES to obtain MimDES-ZIF-8 with different morphologies. All MimDES-ZIF-8 had higher Zn/N ration (>0.25), specific surface area and surface positive charges. The dye adsorption results indicated that MimDES-ZIF-8 showed high adsorption efficiencies for acid fuchsin (all exceeded 97.75 % under pH 7.5) and a fast adsorption rate (exceeding 93 % in 5 min and reaching equilibrium in 60 min). Among MimDES-ZIF-8, the adsorption capacity of ZIF-8-C was 4845.3 mg/g. After five cycles of adsorption, the AF removal efficiency of ZIF-8-C remained over 93.23 %. Moreover, ZIF-8-C also had good adsorption capacity for anionic dyes CR, cationic dyes MB and BB. The adsorption process aligned well with both the Langmuir model and the pseudo-second-order kinetic model. Based on FTIR, XPS, and electrostatic potential calculation, the adsorption mechanism was elucidated.

Synergistic interaction of S-type heterojunction and sulfur vacancies in g-C3N5@Sv-ZnIn2S4 composites: Simultaneous promotion of complete 2,4-dichlorophenol mineralization and Cr(VI) reduction

Constructing efficient heterojunction photocatalysts is an effective measure for degrading pesticides and reducing heavy metals. In this study, g-C3N5@Sv-ZnIn2S4 (g-C3N5@Sv-ZIS) composite with large specific surface area has been successfully prepared by a simple low-temperature water bath method. The g-C3N5@Sv-ZIS composite showed complete mineralization of 2,4-dichlorophenol (2,4-DCP) and reduction of Cr(VI) within 60 min. The results of electron spin resonance spectroscopy, photoelectrochemical characterization, and energy band structure calculations indicated the formation of an S-type heterojunction at the interface of g-C3N5 and Sv-ZIS. In situ XPS analysis showed the transfer of photogenerated charges from g-C3N5 to Sv-ZIS. The molecular structure of 2,4-DCP was analyzed using frontier molecular orbital and electrostatic potential calculations. The possible degradation pathways of 2,4-DCP were proposed based on liquid chromatography– mass spectrometry results. Biotoxicity simulations of the intermediates revealed decreased toxicities. Furthermore, The kinetic rate constant of CZSv-200 for degrading 2,4-DCP and Cr(Ⅵ) in deionized water was approximately 2.20, 3.10 and 2.46, 4.03 times higher than that in lake and sewage plant water, respectively. The composites designed in this study provide reliable theoretical support for the removal of composite pollutants.

Electron-rich COFs with a bis-triphenylamine structure as the main chain: Ultrafast and ultrahigh iodine capture

The construction of ideal adsorbents for the capture of radioiodine usually requires high adsorption capacity and high adsorption rate. However, this is still a challenging problem. The advantages of COFs based on their good crystallinity, pore order, and structural diversity make COFs ideal adsorbents. Here, we developed three novel electron-rich COFs based on the triphenylamine, which have good chemical, thermal, and radiation-resistant stability and are suitable for the harsh environment of radioactive iodine therapy. Upon the introduction of heteroatom N/S, TAPD-PDB and TAPD-TDB exhibited amazing adsorption capacities (75 °C: 7.88 g g−1 and 6.98 g g−1, 25 °C: 4.46 g g−1 and 3.62 g g−1), while the adsorption rates, K80%, are significantly increased to 5.34 g g−1h−1 and 4.22 g g−1h−1, which is higher than most of the reported iodine adsorbents. It was surprising that COFs also have excellent adsorption properties for iodine in cyclohexane solution up to 1260 mg L−1. FT-IR, XPS, Raman and electrostatic potential calculations indicate that the ultrafast and ultrahigh iodine uptake of COFs can be attributed to the interplay of their rich electronic structure, efficient adsorption sites, helical conformation and charge transfer. This study shows the efficient and ultrafast removal of iodine from nuclear wastewater and nuclear exhaust gas by electron-rich COFs.

Recurrent Supramolecular Patterns in a Series of Salts of Heterocyclic Polyamines and Heterocyclic Dicarboxylic Acids: Synthesis, Single-Crystal X-ray Structure, Hirshfeld Surface Analysis, Energy Framework, and Quantum Chemical Calculations

A series of novel salts based on aromatic polyamines and 2,3-pyrazinedicarboxylic acid, such as C10H12N6O5 (1), C10H9ClN6O4 (2), C11H10N8O4 (3), and C14H17N16O5.5 (4) or 3,4-thiophenedicarboxylic acid, such as C10H10N4O4S (5), C10H9ClN4O4S (6), and C10H10N4O4S2 (7), were synthesized and characterized by single-crystal X-ray diffraction. All compounds crystallize in a monoclinic space group. The structure was subjected to complex Hirshfeld surface analysis, molecular electrostatic potential, enrichment ratio, and energy framework calculations. The influence of different cations on the packing of 3-carboxypyrazine-2-carboxylate and 4-carboxythiophene-3-carboxylate anions in the crystal lattice was studied. O…H/H…O interactions are the main contributor in all crystals. In addition, in a series of pyrazine-containing structures, N(C)…H/H…N(C) interactions have relevance, while in a series of thiophene-based compounds, C…H/H…C and S…H(O)/H(O)…S. In addition, Cl-based interactions are observed in compound 2. According to the enrichment ratio calculations, O…H/H…O and C…C are the most preferable interactions in all structures. The energy frameworks are dominated by the dispersive contribution, only in compound 3 is the electrostatic term dominant. The analyzed structures reveal intra- and intermolecular recurrent supramolecular synthons. In both series of crystals, the robust H-bonded centrosymmetric dimer R22(8) as homo- or as heterosynthon (in compounds 2, 3, 6, and 7) and the intramolecular synthon S(7) generated by O-H…O interactions (in compounds 2, 6, and 7) are present. The supramolecular patterns formed by π…π (C…C) and C-O(Cl,S)…C are also noticeable. Notably, a dual synthon linking the supramolecular chain via π…π interactions and the homosynthon R22(8) via N-H…N interactions is visible in both series of new salts. A library of H-bonding motifs at diverse levels of supramolecular architecture is provided. We extended the analysis of intramolecular H-bonding motifs to similar structures deposited in the Cambridge Structural Database. Another important feature is the existence of an intramolecular O…H…O bridge between two neighboring carboxylic groups as substituents in anions in compounds 3 and 5. In this context, we performed quantum theory of atoms-in-molecule calculations to reveal more details.

Oppositely-charged silver nanoparticles enable selective SERS molecular enhancement through electrostatic interactions

Label-free surface-enhanced Raman spectroscopy (SERS) has attracted extensive attention as an emerging technique for molecular phenotyping of biological samples. However, the selective enhancement property of SERS mediated by complicated interactions between substrates and analytes is unfavorable for molecular profiling. The electrostatic force is among the most dominating interactions that can cause selective adsorption of molecules to charged substrates. This means if only negatively- or positively-charged SERS substrates are applied, then considerable SERS information from a portion of analytes would be lost, hindering comprehensive SERS sensing. In this work, we utilize both negatively- and positively-charged colloidal silver (Ag) nanoparticles (NPs) to detect various charged molecules. The negatively-charged citrate-stabilized Ag and the positively-charged Ag prepared via a cetyltrimethyl-ammonium chloride-based charge reversal protocol have been adopted as SERS substrates. The Ag NPs are all relatively well-dispersed with good uniformity. After applying the oppositely-charged NPs to the detection of charged molecules, we find the SERS results explicitly demonstrate the electrostatically-driven SERS selective enhancement, which is further supported and clarified by molecular electrostatic potential calculations. Our work highlights the importance of developing SERS substrates modified with appropriate surface charges for various analytes, and enlightens us that potentially more molecular SERS information can be acquired from complex bio-samples using combinations of oppositely-charged substrates.

Theoretical and experimental investigations on structural, electronic and biological properties of novel carbazate containing furaldehyde based imines

A convenient and facile synthesis of tert‑butyl (E)-2-(furan-2-ylmethylene) hydrazine-1-carboxylate (a) and ethyl (E)-2-(furan-2-ylmethylene) hydrazine-1-carboxylate (b) were accomplished by refluxing t‑butyl/ethyl carbazate with a furaldehyde in solvent ethanol. The interactions between and within two synthesised imine compounds were characterised and identified by the utilisation of spectroscopic techniques in conjunction with X-ray crystallography and theoretical computations. Compound a crystallises in orthorhombic crystal system with Pbca space group, while as compound b crystalizes in monoclinic crystal systems with space groups Cc. The presence of CH…π stacking and π…π stacking interactions are distinguishing characteristic of crystal packing in both target compounds. Their solid-state behaviour was also studied using Hirshfeld surfaces. Crystal packing motifs were investigated with the aid of Hirshfeld surface fingerprint plots. Furthermore, investigations related to calculations of the molecular electrostatic potential and frontier molecular orbital (highest occupied-lowest unoccupied) were carried out for the optimised structure. Finally, Hormone-sensitive lipase (HSL) (PDB-ID 6KEU) protein was used to conduct molecular docking investigations of compound a and b.

Electrostatic Surface Potentials and Chalcogen-Bonding Motifs of Substituted 2,1,3-Benzoselenadiazoles Probed via 77Se Solid-State NMR Spectroscopy.

Chalcogen bonds (ChB) are moderately strong, directional, and specific non-covalent interactions that have garnered substantial interest over the last decades. Specifically, the presence of two σ-holes offers great potential for crystal engineering, catalysis, biochemistry, and molecular sensing. However, ChB applications are currently hampered by a lack of methods to characterize and control chalcogen bonds. Here, we report on the influence of various substituents (halogens, cyano, and methyl groups) on the observed self-complementary ChB networks of 2,1,3-benzoselenadiazoles. From molecular electrostatic potential calculations, we show that the electrostatic surface potentials (ESP) of the σ-holes on selenium are largely influenced by the electron-withdrawing character of these substituents. Structural analyses via X-ray diffraction reveal a variety of ChB geometries and binding modes that are rationalized via the computed ESP maps, although the structure of 5,6-dimethyl-2,1,3-benzoselenadiazole also demonstrates the influence of steric interactions. 77Se solid-state magic-angle spinning NMR spectroscopy, in particular the analysis of the selenium chemical shift tensors, is found to be an effective probe able to characterize both structural and electrostatic features of these self-complementary ChB systems. We find a positive correlation between the value of the ESP maxima at the σ-holes and the experimentally measured 77Se isotropic chemical shift, while the skew of the chemical shift tensor is established as a metric which is reflective of the ChB binding motif.

Prebiotic Chemistry and Sepiolite: A Density Functional Theory Approach

In this study, the molecular interactions of sepiolite, a biocompatibility clay mineral with known as biomaterial, and purine and pyrimidine molecules forming the bases of DNA and RNA molecules were modeled by Density Functional Theory. In addition to the geometry optimization, interaction energy, bond critical point, and electrostatic potential calculations revealed that essential molecules for our source of life interact with the basal surface of the clay. For example, the best interaction energies between bases / sepiolite were found to be -127.47, -121.35 kJ / mol for guanine and cytosine, respectively. Looking at the modeling results, one of the most important factors affecting the interaction energies is H-bond. In order to reveal this, bond critical points analyze were performed and it was computed that a large amount of intermolecular interaction energies came from H-bonds. For example, it has been calculated that close to 70% of the total energy in the guanine/TOT model is from H-bonds. Besides, this value of the cytosine/TOT model was found to be around 72%. The most effective indexes in these two models are 145 and 135, and the H-bond energies were recorded as -22.41 and 31.41 kJ/mol, respectively. Considering all the analyzes run, it can be concluded that the basal surfaces of the sepiolite are a suitable host for the nitrogenous bases, which are the main sources of life.

Crystal structure, theoretical calculations, mechanoluminescence feature and antimicrobial activity based on a double-armed Salamo-type ligand and its trinuclear Cu(Ⅱ) complex

A double-armed salamo-type ligand H4L and its Cu(Ⅱ) complex have been designed and synthesized. The stoichiometric ratios of the prepared H4L and its Cu(Ⅱ) complex were structurally characterized by a variety of analytical and spectroscopic techniques, including elemental analysis, FT-IR, UV–visible, fluorescence spectroscopy, and X-ray crystal diffraction. The results showed that H4L is a linear molecule, while the Cu(Ⅱ) complex is a trinuclear structure with three copper atoms exhibiting different coordination modes due to varying coordination cavities and bridging atoms. The quantum chemical parameters and molecular structures of the H4L and the Cu(Ⅱ) complex have been theoretically calculated and studied. Using molecular electrostatic potential (MEP) and density functional theory (DFT) calculations to understand the selectivity of the H4L and the Cu(Ⅱ) complex chemistry and related reactions. Detailed energy level transitions of the H4L and the Cu(Ⅱ) complex can be determined through time-dependent density functional theory (TD-DFT) calculations. In studying the fluorescence properties of liquid and solid states, it was observed that increasing water content leads to the formation of excimer in both the H4L and its Cu(Ⅱ) complex, the ligand H4L shown good mechanoluminescence, but the Cu(Ⅱ) complex did not. We studied the antimicrobial effectiveness of the H4L and the Cu(Ⅱ) complex against E. coli., the Cu(Ⅱ) complex showed higher inhibition of the pathogenic microorganisms.

Crystal structure elucidation of a geminal and vicinal bis(trifluoromethanesulfonate) ester.

Geminal and vicinal bis(trifluoromethanesulfonate) esters are highly reactive alkylene synthons used as potent electrophiles in the macrocyclization of imidazoles and the transformation of bypyridines to diquat derivatives via nucleophilic substitution reactions. Herein we report the crystal structures of methylene (C3H2F6O6S2) and ethylene bis(trifluoromethanesulfonate) (C4H4F6O6S2), the first examples of a geminal and vicinal bis(trifluoromethanesulfonate) ester characterized by single-crystal X-ray diffraction (SC-XRD). With melting points slightly below ambient temperature, both reported bis(trifluoromethanesulfonate)s are air- and moisture-sensitive oils and were crystallized at 277 K to afford two-component non-merohedrally twinned crystals. The dominant interactions present in both compounds are non-classical C-H...O hydrogen bonds and intermolecular C-F...F-C interactions between trifluoromethyl groups. Molecular electrostatic potential (MEP) calculations by DFT-D3 helped to quantify the polarity between O...H and F...F contacts to rationalize the self-sorting of both bis(trifluoromethanesulfonate) esters in polar (non-fluorous) and non-polar (fluorous) domains within the crystal structure.

Origin of giant enhancement of phase contrast in electron holography of modulation-doped [formula omitted]-type GaN

The electron optical phase contrast probed by electron holography at n-n+ GaN doping steps is found to exhibit a giant enhancement, in sharp contrast to the always smaller than expected phase contrast reported for p-n junctions. We unravel the physical origin of the giant enhancement by combining off-axis electron holography data with self-consistent electrostatic potential calculations. The predominant contribution to the phase contrast is shown to arise from the doping dependent screening length of the surface Fermi-level pinning, which is induced by FIB-implanted carbon point defects below the outer amorphous shell. The contribution of the built-in potential is negligible for modulation doping and only relevant for large built-in potentials at e.g. p-n junctions. This work provides a quantitative approach to so-called dead layers at TEM lamellas.

Synthesis, spectro-themal characterization, DFT calculations and biochemical evaluation of a newly synthesized tridentate Schiff base transition metal complexes

An appropriate conventional method has been utilised to synthesie new tridentate Schiff base ligand 4-chloro-2-((2,4-dihydroxybenzylidene)amino)benzoic acid with Co (II), Ni (II), Cu (II), and Zn (II) complexes. Several spectroscopic(FT-IR, 1H NMR, 13C NMR, UV–Vis, Mass), TGA-DTA, powder X-ray diffraction, and DFT calculations, were used to characterise these complexes. According to these spectroscopic investigations, the ligand coordinated with the metals via carboxylic oxygen, azomethine nitrogen, and hydroxyl oxygen, acting as a tridentate ligand. Appropriate geometry for every complex has been proposed based on spectroscopic and analytical data. In tetrahedral geometry with Co(II), Ni(II), Zn(II), and square planner with Cu(II) ion, the ligand functions as a tridentate via ONO donors. The optimal structure (bond length and bond angle) and chemical reactivity of the ligand and its metal complexes from their Frontier Molecular Orbitals (FMO) and Molecular electrostatic potential (MESP) calculations have been investigated using Density Functional Theory (DFT/B3LYP,6-31G**/6-311G**(d,p), and LanL2DZ basis sets) calculations. In vitro DPPH radical scavenging techniques were used to assess the antioxidant activity of the ligand and its metal complexes. The results indicated that all of the complexes exhibited good antioxidant activity, with the Cu (II) complex being the most potent with the lowest IC50 values. The ligand and complexes in vitro antibacterial activities were further explored by screening them against Gram(+ve) bacteria (Bacillus subtilis) and Gram(−ve) bacteria (E. coli). Significant activity was demonstrated by all synthesised compounds against the tested strains of bacteria. The antifungal activity of complexes against Aspergillus niger and Candida albicans was determined. The results indicated that Cu(II) complex exhibited good antifungal activity against Candida albicans, but not against Aspergillus niger. The fungal strain Aspergillus niger was not significantly inhibited by complexes. The complexes have greater antimicrobial activity than the Schiff base ligand, as indicated by the MIC values.

Unveiling the hydroesterification of 1,3-butadiene with carbonyl cobalt ionic liquids: Facilitation of cationic protonic hydrogen for active species formation

The 1,3-butadiene hydroesterification products, such as methyl pentenoate and dimethyl adipate, play a significant role in the production of nylon, plasticizers, and pharmaceutical intermediates. However, due to its unique π-π conjugated system, slow reaction rate, and difficulties in controlling regioselectivity, butadiene presents itself as an incredibly challenging substrate. The development of efficient and low-cost catalysts has gained substantial attention in both theoretical studies and industrial applications due to the high cost or extremely high pressure requirements. In this study, carbonyl cobalt ionic liquids were innovatively employed as catalysts to facilitate the synthesis of monoesters from hydroesterification of butadiene under mild conditions. A series of carbonyl cobalt ionic liquids with different cations were prepared and characterized for their structural properties using IR, ESI, IC, and DFT calculations. The yield of methyl pentenoate was comparable to that of Co2CO8 at 400 bar, and the catalysts exhibited high selectivity to methyl 3-pentenoates (>95 %), establishing a stable, efficient, and low-cost catalytic system. The experiments revealed that the type of the cation in ionic liquids remarkably influence their catalytic performance. Electrostatic potential calculations further confirmed that this performance is tightly related to the dissociation and migration behaviors of protons, leading to the proposal of a screening method for ionic liquids. In this paper, we further calculated the qualitative reaction kinetics and proposed a reaction mechanism in conjunction with previous studies. The reaction is hypothesized to begin with the formation of the active species HCo(CO)4 by proton exchange of [HX]+[Co(CO)4]−, in line with our experimental findings and theoretical calculations. This study presents an innovative approach to overcome the challenges associated with butadiene hydroesterification and paves the way for the development of more efficient and cost-effective catalytic systems.

Efficient capture of Pd by multidentate S/N-containing group modified materials: An important piece of puzzle for electron transfer ratio ligand design

How to quantitatively describe metal–ligand interactions is the key to design high-affinity ligand. In this study, the electron transfer ratio (ETR), which correlated 34 chemical ligands with the electron donating ability, allowed for obtaining six high affinity multidentate S/N-containing ligands, and the interactions were further analyzed by frontier orbital and electrostatic potential calculation. Furthermore, six corresponding ligand-modified polystyrene framework materials were prepared by efficient derivatization of isothiocyanates and primary amines. The optimal material CMPS-BD had an adsorption capacity up to 4.07 mmol/g with good tolerance to different organic solvents. CMPS-BD exhibited excellent adsorption efficiency in combination with kinetics, thermodynamics, selectivity and regeneration performance. Moreover, the remarkable practicability was achieved as the removal rate reached 99.8 %, and the residual Pd2+ concentrations were reduced to less than 5 mg/L in three kinds of Pd-catalytic reaction waste liquids. Through mechanism analysis, 1 mmol ligand FA ∼ BD could bind 0.75 ∼ 1.74 mmol Pd2+ which was consistent with the ETR tendency, certifying the accuracy and efficiency of this method. Intensive DFT calculations revealed that the optimal ligand BD could generate a variety of spontaneous endothermic intermolecular and intramolecular coordination reactions.

Novel Pyrazole-4-Carboxamide Derivatives Containing Oxime Ether Group as Potential SDHIs to Control Rhizoctonia solani.

In the search for novel succinate dehydrogenase inhibitor (SDHI) fungicides to control Rhizoctonia solani, thirty-five novel pyrazole-4-carboxamides bearing either an oxime ether or an oxime ester group were designed and prepared based on the strategy of molecular hybridization, and their antifungal activities against five plant pathogenic fungi were also investigated. The results indicated that the majority of the compounds containing oxime ether demonstrated outstanding in vitro antifungal activity against R. solani, and some compounds also displayed pronounced antifungal activities against Sclerotinia sclerotiorum and Botrytis cinerea. Particularly, compound 5e exhibited the most promising antifungal activity against R. solani with an EC50 value of 0.039 μg/mL, which was about 20-fold better than that of boscalid (EC50 = 0.799 μg/mL) and 4-fold more potent than fluxapyroxad (EC50 = 0.131 μg/mL). Moreover, the results of the detached leaf assay showed that compound 5e could suppress the growth of R. solani in rice leaves with significant protective efficacies (86.8%) at 100 μg/mL, superior to boscalid (68.1%) and fluxapyroxad (80.6%), indicating promising application prospects. In addition, the succinate dehydrogenase (SDH) enzymatic inhibition assay revealed that compound 5e generated remarkable SDH inhibition (IC50 = 2.04 μM), which was obviously more potent than those of boscalid (IC50 = 7.92 μM) and fluxapyroxad (IC50 = 6.15 μM). Furthermore, SEM analysis showed that compound 5e caused a remarkable disruption to the characteristic structure and morphology of R. solani hyphae, resulting in significant damage. The molecular docking analysis demonstrated that compound 5e could fit into the identical binding pocket of SDH through hydrogen bond interactions as well as fluxapyroxad, indicating that they had a similar antifungal mechanism. The density functional theory and electrostatic potential calculations provided useful information regarding electron distribution and electron transfer, which contributed to understanding the structural features and antifungal mechanism of the lead compound. These findings suggested that compound 5e could be a promising candidate for SDHI fungicides to control R. solani, warranting further investigation.

Effect of hydroxy groups on structural, electronic, and biological properties of methyl carbazate containing hydroxy benzaldehyde-based imines. A combined experimental and theoretical investigation

Interactions present in differently substituted hydroxy based imine derivatives were characterised and identified by the utilisation of spectroscopic techniques in conjunction with X-ray crystallography and theoretical computations. All the target compounds ‘a-c’ crystallises in monoclinic crystal system with P21/c and C2/c space groups. CH…Pi and Pi…Pi interaction are the characteristic interactions present in the target compounds ‘a-c’ The most significant contributions to the crystal packing were found using Hirshfeld surface analysis, and potential contact points were identified. H…H, O…H and C…H contacts and π stacking interactions are the dominant contacts observed in all the crystals these results showed that hydrogen bonding and hydrophobic interactions were significantly present. Furthermore, investigations related to calculations of the molecular electrostatic potential and frontier molecular orbital (highest occupied–lowest unoccupied) were carried out for the optimised structure. The HOMO-LUMO energy gap made it possible to determine the molecule's chemical hardness, chemical inertness, electronegativity, and electrophilicity index, which showed its possible kinetic stability and reactivity. The target compounds' predicted activity spectra (PASS) showed that these compounds exhibit significant Testosterone 17beta-dehydrogenase (NADP+) inhibition activity, with Pa 7.18–7.95. Finally, Testosterone 17beta-dehydrogenase (NADP+) (PDB-ID 3KLP) was used to conduct molecular docking investigations of compounds ‘a-c’. Due to their tiny size and lack of rigidity, which enable them to bind well at any position, a and b exhibit higher binding free energies of -7.08 and -7.00 kcal/mol and inhibition constants of 0.1 and 1.2 µM than compound c.

Kumquat peel-derived biochar to support zeolitic imidazole framework-67 (ZIF-67) for enhancing peracetic acid activation to remove acetaminophen from aqueous solution

This study presents the synthesis of a novel composite catalyst, ZIF-67, doped on sodium bicarbonate-modified biochar derived from kumquat peels (ZIF-67@KSB3), for the enhanced activation of peracetic acid (PAA) in the degradation of acetaminophen (APAP) in aqueous solutions. The composite demonstrated a high degradation efficiency, achieving 94.3% elimination of APAP at an optimal condition of 200 mg L−1 catalyst dosage and 0.4 mM PAA concentration at pH 7. The degradation mechanism was elucidated, revealing that superoxide anion (O2•−) played a dominant role, while singlet oxygen (1O2) and alkoxyl radicals (R–O•) also contributed significantly. The degradation pathways of APAP were proposed based on LC-MS analyses and molecular electrostatic potential calculations, identifying three primary routes of transformation. Stability tests confirmed that the ZIF-67@KSB3 catalyst retained an 86% efficiency in APAP removal after five successive cycles, underscoring its durability and potential for application in pharmaceutical wastewater treatment.

Four novel indole-based hemicyanine dyes: Synthesis, structure determination and spectra analysis

Four hemicyanine dyes (1–4) containing indole group and bearing different substituent in phenyl ring were successfully synthesized. In this study, NMR, elemental analysis and single-crystal analysis were employed to confirm the structures of four newly synthesized compounds. Additionally, electrostatic potential calculations were conducted to enhance the dataset of hemicyanines comprehensively. Furthermore, the optical properties of the resulting hemicyanines were evaluated in organic solvents. The elucidation of the single-crystal structure of the material allows for a deeper understanding of the relationship between its intrinsic structure and properties. This systematic investigation represents an essential initial step towards the development of related photoactive agents for light-based diagnostic and therapeutic applications.