Joyanta Kumar Saha

Context Fluorinated carbonate electrolytes are promising candidates for high-voltage lithium-ion batteries because of their enhanced oxidative stability. However, the effects of fluorination, alkyl chain length, and Li⁺ coordination on their oxidative stability remain unclear. This study investigates the oxidation potentials and electronic properties of a series of fluorinated carbonate electrolytes and Li⁺ complexes. Among the isolated electrolytes, di-2,2,2-trifluoroethyl carbonate had the highest predicted oxidation potential, whereas bis(4,4,4-trifluorobutyl) carbonate had the lowest. Increased fluorination enhances oxidation resistance, whereas longer alkyl chains reduce oxidative stability. Frontier molecular orbital analysis supports these trends. Topological analysis reveals non-covalent electrostatic interactions between the electrolytes and Li⁺, and Li⁺ coordination further improves oxidative stability. The oxidation potentials of both isolated electrolytes and electrolyte/Li⁺ complexes lie beyond the operating voltage range of conventional lithium-ion batteries, indicating excellent resistance to oxidative decomposition. Spin density analysis identifies the preferred oxidation sites in the oxidized species. The calculated oxidation potential of ethyl-2,2,2-trifluoroethyl carbonate agreed with the available experimental value, particularly at the BMK and G4MP2 levels. These findings provide molecular-level insights into the design of fluorinated carbonate electrolytes for next-generation high-voltage lithium-ion batteries. Methods Geometries and oxidation potentials were calculated using B3PW91 and BMK with the aug-cc-pVTZ basis set; G4MP2 calculations were used to assess the oxidation-potential predictions. Solvent effects were treated with the SMD continuum model using a dielectric constant representative of an ethylene carbonate/ethyl methyl carbonate mixture. Optimized structures were verified by vibrational-frequency calculations. HOMO energies, natural bond orbital charges, and Hirshfeld spin densities were analyzed. Quantum chemical calculations were performed with Gaussian 16, and electron-density topology was analyzed with Multiwfn.

Melamine (triazine)‐based crosslinkable waterborne polyurethane (WBPU) dispersions were prepared with defined dimethylolpropionic acid (DMPA, 21.10 mol%) and triazine (0.50 mol) contents. The hydrophobic properties (determined by water swelling (%) and water contact angle), mechanical strength, and adhesive strength of the respective coatings were evaluated. Compared with those of pristine WBPU, the hydrophobicity, adhesion strength, and mechanical strength of crosslinked WBPU increased. The interactions between the urethane‐urea groups and triazine and its derivatives 2,4‐diamino‐6‐dimethylamino‐1,3,5‐triazine (D1), 2,4‐diamino‐6‐diethylamino‐1,3,5‐triazine (D2), 2,4‐diamino‐6‐butylamino‐1,3,5‐triazine (D3), and 2,4,6‐tris[bis(methoxymethyl)amino]‐1,3,5‐triazine (D4 or HMMM) were investigated using density functional theory (DFT) optimization at the M06‐2X/6‐31+G(d,p) level. The DFT results revealed that D4 exhibited the strongest interaction energy and formed hydrogen bonds with WBPU. These theoretical findings strongly matched the experimental findings, because the coating with HMMM improved the protective properties among all the coatings. The addition of defined poly(ethylene oxide) glycol (PEG) also increased the shelf life of the dispersion without sacrificing material properties.

This study investigates the effectiveness of kaolin and bentonite catalysts in improving liquid hydrocarbon yields during the pyrolysis of waste tires. Raw clay, nitric acid-treated clay, and mono- or bimetal-impregnated clay were used as catalysts in the pyrolysis of waste tire. Acid-treated kaolin produced a higher yield of liquid hydrocarbons (43.24-47%) compared to acid-treated bentonite (35.34-41.85%). This improvement in the liquid yield can be attributed to the higher specific surface area and pore diameter of the acid-treated clay in comparison to raw kaolin (39.48%) and raw bentonite (31.62%). Moreover, the use of metal-impregnated catalysts, such as Fe/kaolin and Ni/Fe/kaolin, resulted in higher liquid yields (47%) compared to the 3 M HNO₃-treated kaolin catalyst (43.24%). Gas chromatography-mass spectrometry (GC-MS) analysis confirmed the presence of limonene, a crucial ingredient for commercial perfume production, in the liquid products. The calorific values of oil obtained through kaolin and bentonite catalysis were measured at 13,922 and 10,174 kcal/kg, respectively, further highlighting the potential of these catalysts in waste tire valorization.

A novel cellulose microfibril swelling (Cms) gene of Bacillus sp. AY8 was successfully cloned and sequenced using a set of primers designed based on the conserved region of the gene from the genomic database. The molecular cloning of the Cms gene revealed that the gene consisted of 679 bp sequences encoding 225 amino acids. Further in silico analysis unveiled that the Cms gene contained the NlpC/P60 conserved region that exhibited a homology of 98% with the NlpC/P60 family proteins found in both the strains, Burkholderialata sp. and Burkholderia vietnamiensis. The recombinant Cms enzyme had a significant impact on the reduction of crystallinity indices (CrI) of various substrates including a 3%, a 3.97%, a 4.66%, and a substantial 14.07% for filter paper, defatted cotton fiber, avicel, and alpha cellulose, respectively. Additionally, notable changes in the spectral features were observed among the substrates treated with recombinant Cms enzymes compared to the untreated control. Specifically, there was a decrease in band intensities within the spectral regions of 3000–3450 cm⁻¹, 2900 cm⁻¹, 1429 cm⁻¹, and 1371 cm⁻¹ for the treated filter paper, cotton fiber, avicel, and alpha cellulose, respectively. Furthermore, the recombinant Cms enzyme exhibited a maximum cellulose swelling activity at a pH of 7.0 along with a temperature of 40 °C. The molecular docking data revealed that ligand molecules, such as cellobiose, dextrin, maltose 1-phosphate, and feruloyated xyloglucan, effectively bonded to the active site of the Cms enzyme. The molecular dynamics simulations of the Cms enzyme displayed stable interactions with cellobiose and dextrin molecules up to 100 ns. It is noteworthy to mention that the conserved region of the Cms enzyme did not match with those of the bioadditives like expansins and swollenin proteins. This study is the initial report of a bacterial cellulose microfibril swellase enzyme, which could potentially serve as an additive to enhance biofuel production by releasing fermentable sugars from cellulose.

Hydrogen bonding in polyurethane (PU) is imposed by molecular parameters. In this study, the effect of structural isomerism of certain monomers on hydrogen bonding of waterborne polyurethane (WBPU) was studied theoretically and experimentally. Two dihydroxybenzene (DHB)-based structural isomers such as catechol (CC) and hydroquinone (HQ), with different OH positions on the inner benzene core, had been used. Two series of WBPU dispersions were prepared using CC and HQ with defined contents. The binding energies between the catechol (CC)/hydroquinone (HQ) (respective OH group) and urethane/urea were calculated theoretically. By using a density functional theory (DFT) method, it was found that the largest binding energy between the urea and CC was higher than that of urea and HQ. The FT-IR analysis of synthesized polymer was also carried out to compare the results with the theoretical values. The CC-based polymers showed a stronger hydrogen bond both theoretically and experimentally than those for HQ-based polymers. The higher level of hydrogen bond was reflected in their properties of CC-based polymers. The adhesive strength, thermal stability, and hydrophobicity were higher for CC-based materials than those for HQ-based materials. The adhesive strength was increased 25% with the addition of 2.0 wt% CC content. This adhesive strength slightly deviated at a moderately high temperature of 80 °C.

In this study, we have investigated the binding mechanism of two FDA-approved drugs (ivermectin and levosalbutamol) with the spike protein of SARs-CoV-2 using three different computational modeling techniques. Molecular docking results predict that ivermectin shows a large binding affinity for spike protein (− 9.0 kcal/mol) compared to levosalbutamol (− 4.1 kcal/mol). Ivermectin binds with LEU492, GLN493, GLY496, and TRY505 residues in the spike protein through hydrogen bonds and levosalbutamol binds with TYR453 and TYR505 residues. Using density functional theory (DFT) studies, we have calculated the binding energies between ivermectin and levosalbutamol with residues in spike protein which favor their binding are − 22.4 kcal/mol and − 21.08 kcal/mol, respectively. The natural bond orbital (NBO) charge analysis has been performed to estimate the amount of charge transfer that occurred by two drugs during interaction with residues. Molecular dynamics (MD) study confirms the stability of spike protein bound with ivermectin through RMSD and RMSF analyses. Three different computer modeling techniques reveal that ivermectin is more stable than levosalbutamol in the active site of spike protein where hACE2 binds. Therefore, ivermectin can be a suitable inhibitor for SARS-CoV-2 to enter into the human cell through hACE2.

The thin film of N-doped ZnO/CNT nanocomposite was successfully fabricated on soda lime glass substrate by a simple sol-gel drop-coating method. The structural, morphological, chemical, and optical properties of as prepared samples were characterized by a variety of tools such as X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Fourier Transform Infrared spectroscopy (FT-IR), and UV-visible spectroscopy. The hexagonal crystalline structure was confirmed from XRD measurement without any other impurity phase detection in samples. The N-doped ZnO/CNT composite showed excellent photo-catalytic activity towards cationic methylene blue (MB) dye degradation with 100% removal rate under UV light irradiation as compared to N-doped ZnO (65%) and pure ZnO (47.36%). The convincing performance has also been observed for the case of visible light irradiation. The enhancement of that photocatalytic activity might be due to narrowing the band gap as well as the reduction of electron–hole pair recombination in ZnO matrix with the incorporation of dopant nitrogen and CNT. It is assumed from the obtained results that N-doped ZnO/CNT nanocomposite thin film can be employed as an economically achievable and ecofriendly method to degrade dye with UV and visible light irradiation. Additionally, density functional theory (DFT) calculations were applied to explore the effect of N-doping on electronic structure of ZnO. The computational study has supported the experimental results of significant band gap contraction, which leads to the maximum absorption towards higher wavelength and no appreciable change of lattice parameters after doping. A conceivable photocatalytic mechanism of N-doped ZnO/CNT nanocomposite has been proposed as well.