Density Gradient Analysis Research Articles

Investigations of fluorescence emission Mechanism: Formation of ring-like structures by interactions influenced by hydroxyl group and deprotonation

As one of the gaseous signaling molecules in biological systems, hydrogen sulfide(H2S) is involved in numerous physiological processes and diseases. Therefore, rapid, effective, and real-time detection of H2S is of great importance. Based on its excellent optical properties, dicyanoisophorone has attracted much attention in recent years, and a large number of corresponding probes have been developed to detect H2S in biological systems. In this paper, the fluorescence mechanisms of three dicyanoisophorone-based fluorescent probes are investigated and the near-infrared (NIR) fluorescence attribution of the products is discussed by density-functional theory and time-dependent density-functional theory methods. Frontier molecular orbital analysis shows that the non-fluorescence of the probes is attributed to the photo-induced electron transfer process. Structural change and reduced density gradient analyses indicate that the position of the hydroxyl group and the deprotonation have a non-negligible influence on the interactions within the products. The five- or six-membered ring-like structures formed by interactions make the molecule stain as a planar and the fluorescence emission, while the twist exists the fluorescence quenching. In addition, spectral information shows that the emission of NIR fluorescence originates from the deprotonated form of the product.

Rational Design, Synthesis, and Computational Investigation of Dihydropyridine [2,3-d] Pyrimidines as Polyphenol Oxidase Inhibitors with Improved Potency.

Polyphenol oxidase (PPO) is an industrially important enzyme associated with browning reactions. In the present study, a set of ten new dihydropyridine [2,3-d] pyrimidines (TD-Hid-1-10) were synthesized and was found to be proven characteristically by 1H NMR, 13C NMR, IR, elemental analysis, and assessed as possible PPO inhibitors. PPO was purified from banana using three-phase partitioning, achieving an 18.65-fold purification and 136.47% activity recovery. Enzyme kinetics revealed that the compounds TD-Hid-6 and TD-Hid-7 are to be the most potent inhibitors, exhibiting mixed-type inhibition profile with IC50 values of 1.14 µM, 5.29 µM respectively against purified PPO enzyme. Electronic structure calculations at the B3LYP/PBE0 level of theories using def-2 SVP, def2-TZVP basis sets with various molecular descriptors characterized the electronic behavior of studied derivatives TD-Hid-1-10. Molecular electrostatic potential (MEP) and reduced density gradient analyses of RDG-NCI provided insights into charge distributions and weak intermolecular interactions. Docking study simulations predicted binding poses within crucial amino acid sequence in the 2y9x enzyme's active site, which is typically similar in sequence to the PPO form is not allowed. Ligands were analysed in terms of binding energies, inhibitor concentrations (mM) and various molecular interactions such as H-bonds, H-carbon, π-carbon, π-sigma, π-sigma, π-π T-shaped, π-π stacked, π-alkyl, Van der Waals and Cu interactions. The lowest binding energy (-7.83kcal/mol) and the highest inhibitory effect (1.83 mM) were shown by the ligand Td-Hid-6, which forms H-bonds with Met280 and Asn260, exhibits π-sigma interactions with His61 and π-alkyl interactions with Val283. Other ligands also showed different interactions with various amino acids; for example, the Td-Hid-1 ligand formed H-bonds with His244 and showed π-sigma interactions with His244 and Val283.

Density functional theory and spectroscopic analysis of stigmasterol from Garcinia wightii: Deciphering its inhibitory potential against drug-resistant tuberculosis via insilico molecular docking and molecular dynamics simulations

This study investigates the molecular structure and electronic properties of stigmasterol, isolated from Garcinia wightii, using density functional theory (DFT) alongside experimental techniques including FT-IR, FT-Raman, UV–Vis, 1H and 13C NMR spectroscopy. Theoretical predictions are compared with experimental results, facilitated by vibrational energy distribution analysis for unambiguous vibrational wavenumber assignments. Natural bond orbitalanalyzes reveal donor-acceptor bond energies and electron densities, while Fukui functions identify reactive sites susceptible to electrophilic and nucleophilic attacks. Electronic properties are further explored through various analyzes, unveiling reactive surface sites. Non-covalent interactions are examined using reduced density gradient analysis. Assessment of absorption, distribution, metabolism, and excretion attributes aids in drug discovery efforts. Molecular docking studies against 20 target proteins for antitubercular screening show a stable glide score of -9.52 kcal/mol for the protein 4FDO (Mycobacterium tuberculosis DprE1 in complex with CT319). Molecular dynamics simulations over 100 ns indicate the stability of the ligand-protein complex, suggesting its potential as an antituberculosis agent. Stigmasterol's structural, vibrational, electronic, and topological properties are thoroughly investigated, revealing its ring skeleton with a flexible isooctyl side chain, adhering to C1 point group symmetry. Steric and stereo electronic interactions play crucial roles in conformation and binding to target proteins. Theoretical and experimental analyzes align, confirming the compound's bioactive properties. This comprehensive investigation underscores stigmasterol's potential as a tuberculosis treatment option, providing valuable insights into its structural characteristics and therapeutic possibilities.

Insights into 5-fluorouracil anti–cancer drug encapsulation within the pristine and palladium-doped carbon, silicon-carbide, and germanium-carbide nanotubes: A DFT investigation for advanced nanomedicine applications

In this study, we investigated the interaction and binding properties of 5-Fluorouracil (5-FU), an anti-cancer drug, encapsulated within pristine and palladium-doped carbon, silicon-carbide, and germanium-carbide nanotubes (CNT, SiCNT, GeCNT). Using density functional theory (DFT), we conducted a comprehensive analysis at both aqueous and gas phases. This included geometrical, structural, electrical, bonding, and thermodynamic properties, optimized geometries, adsorption energies, quantum molecular descriptors, frontier molecular orbitals, and topological parameters at the M06-2X level of theory. Our findings indicate that Pd-doping enhances the encapsulation capabilities of nanotubes, strengthening interactions with 5-FU and improving water solubility. Calculations of recovery time required for drug release suggest that Pd-doped nanotubes effectively control the release of 5-FU. Notably, the decapsulation time of 5-FU from of Pd-doped nanotubes was longer in the gas phase than in aqueous conditions. Using the quantum theory of atoms in molecules (QTAIM) method, we investigated intermolecular interactions and critical bonding points. Natural bond orbital (NBO) analysis revealed enhanced stabilization of the 5-FU molecule post-encapsulation, with charge transfer primarily directed from nanotubes to the 5-FU. Hirshfeld surface analysis highlighted that hydrogen bonds between 5-FU active sites and nanotubes are crucial in encapsulation and fixation. Reduced Density Gradient (RDG) analysis confirmed Pd-doping as a primary source of strong attractive interactions in 5-FU/Pd-doped nanotube complexes compared to pristine nanotubes.

Ab Initio Study of the Graphyne-like γ-SiC Nanoflake for Toxic Gas-Sensing Applications.

This study focuses on the geometrical, electronic, and optical properties of the γ-graphyne-like novel γ-SiC nanoflake of the γ-silicon carbide (SiC) monolayer using density functional theory calculations. γ-SiC was revealed to be a stable semiconducting nanoflake confirmed by a negative cohesive energy, real vibrational frequencies, and a 1.749 eV energy gap. The adsorption of COCl2, HCN, PH3, AsH3, CNCl, and C2N2 toxic gases on the γ-SiC nanoflake is also studied, which revealed an attractive gas-nanoflake interaction with the adsorption energy ranging from -0.21 to -0.38 eV. The adsorption results in a significant charge transfer between gas-adsorbent complexes. A significant variation in the energy gap and electrical conductivity was observed due to gas adsorption. γ-SiC showed maximum sensitivity at room temperature for CNCl gas. The entire process of adsorption is exothermic and thermodynamically stable. γ-SiC showed a high absorption coefficient over 104 orders with a significant variation in the absorption peak intensity and blue peak shifting. According to the quantum theory and reduced density gradient analysis, all of the gases are physisorbed on the γ-SiC nanoflake due to van der Waals interactions. The obtained results signify the usability of γ-SiC as a potential toxic gas sensor.

Size-Dependent Fullerenes for Enhanced Interaction of l-Leucine: A Combined DFT and MD Simulations Approach.

Fullerene-based biosensors have received great attention due to their unique electronic properties that allow them to transduce electrical signals by accepting electrons from amino acids. Babies with MSUD (maple syrup urine disease) are unable to break down amino acids such as l-leucine, and excess levels of the l-leucine are harmful. Therefore, sensing of l-leucine is foremost required. We aim to investigate the interaction tendencies of size-variable fullerenes (CX; X = 24, 36, 50, and 70) toward l-leucine (LEU) using density functional theory (DFT-D3) and classical molecular dynamics (MD) simulation. The C24 fullerene shows the highest affinity of the LEU biomolecule in the gas phase. Smaller fullerenes (C24 and C36) show stronger interactions with leucine due to their higher curvature in water environments. Moreover, recovery times in the ranges of 1010 and 104 s make it a viable candidate for the isolation application of LEU from the biological system. Further, the interaction between LEU and fullerenes is in line with the natural bond order (NBO) analysis, Mulliken charge analysis, quantum theory atom in molecule (QTAIM) analysis, and reduced density gradient (RDG) analysis. At 310 K, employing the explicit water model in classical MD simulations, fullerenes C24 and C36 demonstrate notably elevated binding free energies (-24.946 kJ/mol) in relation to LEU, showcasing their potential as sensors for l-leucine. Here, we demonstrate that the smaller fullerene exhibits a higher potential for l-leucine sensors than the larger fullerene.

Theoretical Analysis of Coordination Geometries in Transition Metal-Histidine Complexes Using Quantum Chemical Calculations.

A theoretical investigation utilizing density functional theory (DFT) calculations was conducted to explore the coordination complexes formed between histidine (His) ligands and various divalent transition metal ions (Mn2+, Fe2+, Co2+, Ni2+, Cu2+, and Zn2+). Conformational exploration of the His ligand was initially performed to assess its stability upon coordination. Both 1:1 and 1:2 of metal-to-ligand complexes were scrutinized to elucidate their structural features and the relative stability of the complexes. This study examined the ability of His to act as a bidentate or tridentate coordinating ligand, along with the differences in coordination geometry when solvent effects were incorporated. The reduced density gradient (RDG) analysis and local electron attachment energy (LEAE) analysis were employed to elucidate the interaction planes and the nucleophilic and electrophilic properties. The electronic properties were analyzed through electrostatic potential (ESP) maps and natural population analysis (NPA) of atomic charge distributions. This computational study provides valuable insights into the diverse coordination modes of His and its interactions with divalent transition metal ions, contributing to a better understanding of the role of this amino acid ligand in the formation of transition metal complexes. The findings can aid in the design and construction of self-assembled structures involving His-metal coordination.

Single-crystal X-ray structure, theoretical (Hirshfeld, electronic properties, NBO, NLO, RDG), and molecular docking studies of three phthalimidoethanesulfonamide derivatives

The three N-substituted-2-phtalimidoethanesulfonamide derivatives, 2-(1,3-dioxoisoindolin-2- yl)-N-(2-isopropylphenyl)ethane-1-sulfonamide (I), N-(2,6-dimethylphenyl)-2-(1,3-dioxoiso indolin-2-yl)ethane-1-sulfonamide (II) and 2-(2-(morpholinosulfonyl)ethyl) isoindoline-1,3‑dione (III), were analyzed using a combined approach including single-crystal X-ray diffraction (SC-XRD), theoretical calculations with Density Functional Theory (DFT), and molecular docking studies. Phthalimide and sulfonamide compounds have recently attracted attention for their inhibitory properties against AChE and BChE enzymes. In this study, molecular and crystal structures of compounds have been confirmed by the SC-XRD technique. Optimized molecular geometries and vibrational modes have been examined and compared to experimental results. Frontier molecular orbital (HOMO-LUMO) energies, molecular electrostatic potential (MEP), natural bond orbital (NBO) analysis, and non-linear optical (NLO) properties have been investigated by DFT/B3LYP/6–311G++(d,p) method. The reduced density gradient (RDG) analysis has been performed to analyze the non-covalent interactions. The Hirshfeld surfaces and 2D fingerprint analyses have been used to determine the intermolecular interactions of compounds. Moreover, in silico docking studies are performed to investigate the interactions between N-substituted-2-phtalimidoethane sulfonamide derivatives and AChE and BChE enzymes.

Natural deep eutectic solvent-ultrasound for the extraction of flavonoids from Fructus aurantii: Theoretical screening, experimental and mechanism

To reduce the environmental pollution caused by organic solvents and improve the extraction efficiency, a green and high-effective natural deep eutectic solvent (NADES) was screened out and prepared for the extraction of flavonoids from Fructus aurantii based on the COMOS-RS and experimental verification. The results showed the results of theoretical screening and experimental verification were consistent, and Ch-Lea was the best extraction solvent, which further proved the COMOS-RS was an efficient tool for the solvent screening. Then, the extraction conditions were investigated. The optimum extraction conditions were as follows: molar ratio (1:2), water content (30%), solid–liquid ratio (1/60 g/g) and extraction time (15 min), yet the extraction temperature and power did not significantly affect the extraction yield. Under the optimal extraction condition, the extraction yield of flavonoids was 122.68 mg/g. Compared with the traditional extraction solvents (methanol and ethanol), Ch-Lea has a higher extraction yield. And the green assessment was conducted based on Eco-Scale methodology, which results indicated the Ch-Lea was more environmentally friendly than methanol and ethanol. Meanwhile, the Ch-Lea has good reusability, and the extraction yields from four reuses were 122.68 mg/g, 125.13 mg/g, 122.56 mg/g and 105.63 mg/g, respectively. Moreover, the extraction mechanism was delved into using molecular dynamics (MD) simulation and reduced density gradient (RDG) analysis. The hydrogen bond interaction, particularly the O-H bonds, between Ch-Lea and the naringin molecule emerged as the primary force driving the extraction process. In summary, Ch-Lea is a green, economical, and highly effective solvent, making it a promising candidate for flavonoid extraction from Fructus aurantii. Its potential as an alternative to traditional extraction solvents further underscores its value.

Novel series of hydrazones carrying pyrazole and triazole moiety: Synthesis, structural elucidation, quantum computational studies and antiviral activity against SARS-Cov-2

The novel series of hydrazones carrying both pyrazole and triazole moiety were synthesized and characterized using single crystal X-ray diffraction studies. It is found that the compound crystallizes in the triclinic system in the space group P1̅. Hirshfeld analysis was carried out to visualize the noncovalent intermolecular interactions which are responsible for molecular packing in the crystal. Further, density functional theory (DFT) calculations were used to calculate optimized molecular structure, stability, and a few of the quantum chemical parameters. Derived results are in good agreement with the experimentally obtained results. Analysis of frontier molecular orbitals (HOMO and LUMO) and their energy gap of the optimized structure revealed that the compound is stable in the gaseous state. Molecular electron densities, and electrostatic potential maps provide the reactive site and charge distribution of triazole group. Quantum theory of atoms in molecules (QTAIM) and reduced density gradient (RDG) analysis were carried out to explore the weak interactions present in the molecule. In addition, the synthesized compound was investigated as an inhibitor for SARS CoV-2 protease using in-silico molecular docking analysis to understand the mode of binding. The docking results showed the good binding score with Mpro protease 6LU7. Further, molecular dynamics (MD) were carried out for the best hit docked complexes.

Self-associates of 1,2,4-triazole: FTIR studies, quantum chemical calculations and topological analysis

The Fourier Transform Infrared (FTIR) spectroscopic technique has been employed to study the self-associates of 1,2,4-triazole (Htrz) in solid phase. The self-associates have been identified using density functional theory (DFT) calculations carried out on various multimers of Htrz under B3LYP/6–311++ G(d, p) level. Comparison of the experimental and theoretical frequencies of N−H andC−Hstretching absorptional bands indicate that Htrz exists as multimers upto hexamer. The Occupancy of the anti-bonding orbitals of the proton donors, Natural bond Orbital (NBO), Frontier Molecular Orbital (FMO), Electrostatic potential surface (ESP), reduced density gradient (RDG) analyses have also been executed. In addition, topological parameters have also been analysed to characterize the hydrogen bonds and proton donating covalent bonds. The analyses show that pentamer is the most stable among all the H-bonded associates and the dimer 3 in which classical and non-classical H-bond interaction coexists is the least stable. The topological parameter values suggest that the N−H bonds of dimer1/pentamer are with the highest/smallest covalent character. The criteria proposed in literature to describe the covalent nature of bonds, in particular proton donor bonds, appears to fails in the Htrz dimer in which classical and non-classical hydrogen bonds coexist.

Tandem Four-Component Reaction to Access Fused Polycycles Exhibiting Aggregation-Enhanced Through-Space Charge Transfer Emission.

Rapid construction of new fluorescence emitters is essential in advancing synthetic luminescent materials. This study illustrated a piperidine-promoted reaction of chiral dialdehyde with benzoylacetonitrile and malonitrile, leading to the formation of the 6/6/7 fused cyclic product in good yield. The proposed reaction mechanism involves a dual condensation/cyclization process, achieving the formation of up to six bonds for fused polycycles. The single crystal structure analysis revealed that the fused cyclic skeleton contains face-to-face naphthyl and cyanoalkenyl motifs, which act as the electronic donor and acceptor, respectively, potentially resulting in through-space charge transfer (TSCT) emission. While the TSCT emissions were weak in solution, a notable increase in luminescence intensity was observed upon aggregation, indicating bright fluorescent light. A series of theoretical analyses further supported the possibility of spatial electronic communication based on frontier molecular orbitals, the distance of charge transfer, and reduced density gradient analysis. This work not only provides guidance for the one-step synthesis of complex polycycles, but also offers valuable insights into the design of aggregation-enhanced TSCT emission materials.

Hydrogen bond thermotropic ferroelectric liquid crystal of DL-tartaric acid and 4-heptyloxybenzoic acid (1:1): Experimental and density functional theory (DFT) approach

The current research work incorporates structural, experimental and computational studies of a hydrogen bond thermotropic ferroelectric liquid crystal (HBTFLC) complex synthesised from DL-tartaric acid (DLTA) and 4-heptyloxybenzoic acid (7OBA) with 1:1 ratio. Spectroscopic studies (XRD, NMR, FTIR, UV–Vis) and Density Functional Theory (DFT) are utilized to confirm intermolecular hydrogen bonds in the synthesised complex. Polarizing Optical Microscope (POM) study confirms the phase sequence (N*, Sm C*, Sm F* and Sm G*) while Differential Scanning Calorimetry (DSC) explore the thermal properties of the mesophases. The Frontier Molecular Orbital (FMO) and Molecular Electrostatic Potential (MEP) surface analysis also explore the donor-acceptor interactions, stability and chemical reactivity of the complex. The nature of H-bond is estimated by Natural Bond Orbital (NBO) studies with the support of Atom-in-Molecules (AIM) and Reduced Density Gradient (RDG) analysis. Nonlinear Optical (NLO) properties of the complex are studied by calculating its polarizability and hyperpolarizability.

Investigating the potential of graphene and nitrogen carbide nanosheets as efficient sensors for drug detection through theoretical analysis

Due to the advancements in nanoscience, there has been a steady rise in the utilization of low-dimensional nanomaterials as efficient sensors in clinical practice. This research undertook a theoretical investigation aimed at proposing a prospective sensor for the allopurinol (APN) drug. The study focused on examining the fundamental interactions between the drug molecule and two nanosheets, namely graphene (GNS) and nitrogen carbide (NC3NS), employing DFT B3LYP/6-31G(d,p) in both aqueous and gaseous media. A range of adsorption energy (Eads) values for APN-NC3NS conjugated structures (CSs) was observed, ranging between −31 kcal mol−1 and −20 kcal mol−1, indicating weak chemisorption. This observed interaction can be attributed to the transfer of charge from APN to NC3NS, a phenomenon verified and characterized using reduced density gradient analysis, natural bond analysis, and the quantum theory of atoms in molecules. The APN-NC3NS conjugated structure exhibited the most significant reductions in the energy gap (Eg), with a decrease of 42.37 % in the gas phase and 30.11 % in water. This observation was further supported by frontier molecular orbital (FMO) and molecular electrostatic potential (MEP) analyses. Additionally, the NC3NS nanosheet’s advantageous ability to quickly recover (within the millisecond range) positions it as a promising candidate for the efficient detection of APN molecules.

Computational assessment of the use of graphene-based nanosheets as PtII chemotherapeutics delivery systems.

Graphene is the newest form of elemental carbon and it is becoming rapidly a potential candidate in the framework of nano-bio research. Many reports confirm the successful use of graphene-based materials as carriers of anticancer drugs having relatively high loading capacities compared with other nanocarriers. Here, the outcomes of a systematic study of the adsorption behavior of FDA approved PtII drugs cisplatin, oxaliplatin, and carboplatin on surface models of pristine, holey, and nitrogen-doped holey graphene are reported. DFT investigations in water solvent have been carried out considering several initial orientations of the drugs with respect to the surfaces. Adsorption free energies, calculated including basis set superposition error (BSSE) corrections, result to be significantly negative for many of the drug@carrier adducts indicating that tested layers could be used as potential carriers for the delivery of anticancer PtII drugs. The reduced density gradient (RDG) analysis allows to show that many kinds of non-covalent interactions, including canonical H-bond, are responsible for the stabilization of the formed adducts.

Multifaceted investigation of Sulfamerazine: Insights from computational methods, experimental techniques, and molecular simulations

The powerful sulfonamide antibiotic Sulfamerazine has been the subject of in-depth study to clarify its complex molecular interactions. In order to understand Sulfamerazine's pharmacological behaviour and interactions with biological components, this comprehensive study uses computational tools such as Density Functional Theory (DFT) calculations, spectroscopic analyses, and molecular docking simulations. Exploitation B3LYP/6-311++G(d,p) basis set, DFT simulations have provided important new understandings of the structure, vibrational properties, and binding mechanisms of this system. Vibrational assignments have been conducted by analyzing individual vibrational modes and comparing them to experimental data. The molecule's weak interactions have been identified grounded on electron density using Reduced Density Gradient Analysis. Fukui and MEP plot analyses have been employed to pinpoint the molecule's electrophilic and nucleophilic sites. Frontier molecular orbital analysis supported the observation of charge transfer within the molecule. Sulfamerazine is a viable option for further pharmaceutical development, as shown by drug-likeness and ADME (absorption, distribution, metabolism, and excretion) studies. In docking analysis, the inhibitor 6qzh stood out as particularly potent, capable of forming up to three hydrogen bonds, resulting in a binding energy of -8.2 kcal/mol. Molecular dynamics simulations have also shed light on the stability, solubility, and possible interactions of Sulfamerazine in diverse settings. This all-encompassing strategy promises to increase our understanding of the mechanism of action of Sulfamerazine, creating new opportunities for the logical development of more potent pharmaceuticals.

Bifonazole caffeate: The first molecular salt of bifonazole with enhanced biopharmaceutical property based on experiments and quantum chemistry research

In order to make novel breakthroughs in molecular salt studies of BCS class-IV antifungal medication bifonazole (BIF), a salification-driven strategy towards ameliorating attributes and aiding augment efficiency is raised. This strategy fully harnesses structural characters together attributes and benefits of caffeic acid (CAF) to concurrently enhance dissolvability and permeability of BIF by introducing the two ingredients into the identical molecular salt lattice through the salification reaction, which, coupled with the aroused potential activity of CAF significantly amplifies the antifungal efficacy of BIF. Guided by this route, the first BIF-organic molecular salt, BIF-CAF, is directionally designed and synthesized with satisfactorily structural characterizations and integrated theoretical and experimental explorations on the pharmaceutical properties. Single-crystal X-ray diffraction resolving confirms that there is a lipid-water amphiphilic sandwich structure constructed by robust charge-assistant hydrogen bonds in the salt crystal, endowing the molecular salt with the potential to enhance both dissolvability and permeability relative to the parent drug, which is validated by experimental evaluations. Remarkably, the comprehensive DFT-based theoretical investigations covering frontier molecular orbital, molecular electrostatic potential, Hirshfeld surface analysis, reduced density gradient, topology, sphericity and planarity analysis strongly support these observations, thereby allowing some positive relationships between macroscopic properties and microstructures of the molecular salt can be made. Intriguingly, the optimal properties, together with the stimulated activity of CAF markedly augment in vitro antifungal ability of the molecular salt, with magnifying inhibition zones and reducing minimum inhibitory concentrations. These findings fill in the gaps on researches of BIF-organic molecular salt, and adequately exemplify the feasibility and validity by integrating theoretical and experimental approaches to resolve BIF’s problems via the salification-driven tactic.

Investigations on Growth, Characterization, NCI-RDG, AIM, Molecular Docking and In-Silico ADME Properties of 1,2-Benzene Dicarboxylic Acid Anhydride

Superior single crystal of 1,2-benzene dicarboxylic acid anhydride additionally called Phthalic anhydride (PAN) was developed via solution growth at low temperatures. Single crystal X-ray diffraction investigation revealed the crystal system and unit cell characteristics. The phase stability and crystalline nature were uncovered by powder X-ray diffraction analysis. FT-IR examination was done for the titular material so as to survey the various functional groups. With the use of the VEDA program's relevant resources, vibrational assignments have been made on the concept of Potential Energy Distribution (PED). Density Functional Theory (DFT) was employed to smooth out the molecular structure of PAN and was additionally utilized to consider FT-IR spectrum at molecular level. Non covalent interactions reduced density gradient (NCI-RDG) analysis has been used for the prediction of the weak interaction in the actual space in terms of the electron density along with its derivatives for PAN. Atoms in Molecules (AIM) analysis was carried for out for PAN. The docking research of the small molecule (PAN) with target protein confirmed that this is a great molecule which docks nicely with numerous targets associated with Hypoxia Inducible Factor 1-α. The absorption, distribution, metabolism, excretion (ADME) characteristics have been calculated with the assist of online server preADMET.

Thiosemicarbazone derivatives as potent antidiabetic agents: Synthesis, in vitro, molecular docking and DFT investigations

A library of thiosemicarbazones derivatives have been synthesized by multi step reactions, characterized and screened for their in vitro α-amylase and α-glucosidase inhibitory actions. Among them, three compounds including 4b (IC50 = 3.18 ± 1.72 and 2.11 ± 1.29 µM), 4a (IC50 = 5.16 ± 1.12 and 7.23 ± 0.11 µM), and 4 g (IC50 = 7.13 ± 1.21 and 9.53 ± 0.29 µM) are found as potential dual inhibitors of α-amylase and α-glucosidase enzymes, powerfull than the standard acarbose drug (IC50 = 21.55 ± 1.31 and 16.65 ± 0.07 µM). In addition, compounds 4c, 4f, 4 h, 4d, and 4e indicated significant to less inhibitory potential. Molecular docking was performed to know the binding affinities and various interactions between the synthesized compounds and targeted proteins. For the docking analysis, the protein structure of α-amylase was taken from the Protein Data Bank (PDB) with the code 3BAJ, derived from Homo sapiens. Meanwhile, the protein structure of α-glucosidase was obtained from Beta vulgaris with the PDB code 3W37. The chemical nature of the product compounds was identified using the density functional theory (DFT) method, and the calculations were performed using the B3LYP/6–311++G(d,p) method. Intramolecular interactions were explored using DFT-d3 and Reduced Density Gradient (RDG) analysis. Furthermore, the chemical nature of all the compounds was identified using TD-DFT at the CAM-B3LYP/6–311++G(d,p) method. Among the synthesized compounds, 4a, 4b, and 4g show similar inhibition activities with targeted proteins. Similar activities have been confirmed using the TD-DFT method. The energy gap between the highest occupied molecular orbitals and lowest unoccopied was found as, 6.07, 6.08, and 6.07 eV, respectively. The similarty in energy gap indicated these compounds have similiar reactivity nature.

Selective visual staining of polyurethane microplastics by novel colorimetric and near-infrared (NIR) fluorescent dye: Application to environmental water and natural soil samples

Microplastics can cause environmental pollution and ecosystem destruction as well as human health problems. Among the types of microplastics, polyurethane (PU) is particularly resistant to heat and difficult to decompose, causing disposal problems, and is evaluated as one of the most hazardous polymers. We present a novel colorimetric and near-infrared (NIR) fluorescence dye, (E)-N-(2-((4-(diphenylamino)benzylidene)amino)phenyl)− 7-nitrobenzo[c][1,2,5]oxadiazol-4-amine (DPNA), designed for selective visual PU microplastic staining. The intramolecular charge transfer (ICT) properties of DPNA are demonstrated through density functional theory (DFT) calculations along with solvatochromic shift. DPNA exhibits red color and red fluorescence emission, showing promising potential as a staining dye. To achieve selective PU microplastic staining, we establish an optimized experimental procedure with the staining dye DPNA by evaluating the staining efficiency under different staining solvent compositions and staining times. DPNA can distinguish PU by both red fluorescence signal and red coloration among different types of microplastics. In addition, DPNA well stain fresh PUs with diverse sizes and at various pH range of 5–9, and the aged PUs can also be dyed as effectively as the fresh PU. Most importantly, DPNA selectively stains PU among 11 types of microplastics and 5 types of natural particles in environmental water and soil with and without any pre-treatments. The adsorption mechanism of DPNA on PU microplastic is demonstrated through field emission scanning electron microscopes (FE-SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and non-covalent interaction (NCI)-reduced density gradient (RDG) analyses, and proposed that intermolecular hydrogen bonding has a significant effect.