Orbital Analysis Research Articles

Dissipated correction map method with trapezoidal rule for the simulations of gravitational waves from spinning compact binary

ABSTRACT The correction map method means extended phase-space algorithm with correction map. In our research, we have developed a correction map method, specifically the dissipated correction map method with trapezoidal rule, for numerical simulations of gravitational waves from spinning compact binary systems. This new correction map method, denoted as $CM3$, has shown remarkable performance in various simulation results, such as phase-space distance, dissipated energy error, and gravitational waveform, closely resembling the high-order precision implicit Gaussian algorithm. When compared with the previously used mid-point map which is denoted as $C_2$, the $CM3$ consistently exhibits a closer alignment with the highly accurate Gaussian algorithm in waveform evolution and orbital trajectory analysis. Through detailed comparisons and analyses, it is evident that $CM3$ outperforms other algorithms, including $CM2$ and $C_2$ mentioned in this paper, in terms of accuracy and precision in simulating spinning compact binary systems. The incorporation of the trapezoidal rule and the optimization with a scale factor $\gamma$ have significantly enhanced the performance of $CM3$, making it a promising method for future numerical simulations in astrophysics. With the groundbreaking detection of gravitational waves by the LIGO/VIRGO collaboration, interest in this research domain has soared. Our work contributes valuable insights for the application of matched filtering techniques in the analysis of gravitational wave signals, enhancing the precision and reliability of these detection.

Probing the Local Environment in Potassium Salts and Potassium-Promoted Catalysts by Potassium Valence-to-Core X-ray Emission Spectroscopy.

Potassium plays an important role in biology as well as a promoter in heterogeneous catalysis. There are, however, limited characterization techniques for potassium available in the literature. This study elucidates the potential of element-selective X-ray emission spectroscopy (XES) for characterizing the coordination environment and the electronic properties of potassium. A series of XES measurements were conducted, primarily focusing on the VtC transition (Kβ2,5) of potassium halides (KCl, KBr, and KI) and oxide-bound potassium salts, including potassium nitrate (KNO3) and potassium carbonate (K2CO3). Across the series of potassium halides, the VtC transition energy is observed to increase, as accurately reproduced by TDDFT calculations. Molecular orbital analysis suggests that the Kβ2,5 transition is primarily derived from halide np contributions, with the primary factor influencing the energy shift being the metal-ligand distances. For oxide ligands, an additional Kβ″ transition appears alongside the Kβ2,5, which is attributed to a low-energy ligand ns, as elucidated by theoretical calculations. Finally, the XES spectra of two potassium-promoted catalysts for ammonia decomposition/synthesis were measured. These spectra show that potassium within the catalyst is distinct from other K salts in the VtC region, which could be promising for understanding the role of potassium as an electronic promoter.

An activatable NIR turn-on fluorescent probe for copper (II) ion and live cell imaging

Herein we have reported a fluorescent probe (MB-M) based on MB derivative for Cu2+ ions detection. The probe was well characterized by 1H NMR, 13C NMR and HR-MS spectrum. Probe MB-M showed naked-eyes recognition to Cu2+ as color change from colorless to indigo. The probe exhibited promising features such as high fluorescence and UV–vis selectivity, fast response (5 mint), workable at pH 2–7, and low limit of detection (LOD = 0.33 µM). Probe MB-M was also used for Cu2+ ions imaging in HepG-2 cells and detection in daily life (Test Strip and lake water). Moreover, non-covalent interaction (NCI) and quantum theory of atoms in molecules (QTAIM) analysis were used to study the interaction between MB-M and Cu2+ ions. By examining the electronic characteristics of the complex using natural bond orbital (NBO), electron density difference (EDD), and frontier molecular orbital (FMO) analysis, the sensitivity of MB-M towards Cu2+ ions were investigated. The results illustrated that the interactions between MB-M and Cu2+ ions involved chemisorption.

Design, synthesis, and characterization of a novel pH-responsive azo dye incorporating a 1,3,4-thiadiazole ring for advanced textile applications

This study presents the synthesis and comprehensive characterization of a novel azo dye derived from 2-(5-amino-1,3,4-thiadiazol-2-yl) phenol (1a). The synthesis was initiated by reacting salicylic acid with thiosemicarbazide in the presence of phosphorus oxychloride (POCl3), yielding an 89 % conversion to compound 1a. The subsequent diazotization and coupling of 1a under alkaline conditions led to the formation of the azo dye (1b). Structural elucidation was confirmed through Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The incorporation of the 1,3,4-thiadiazole ring is significant due to its known influence on enhancing dye stability, reactivity, and potential biological activities, while the salicylic acid moiety contributes to the dye's pH responsiveness. A notable pH-dependent color transition from yellow (pH < 6.0) to red (pH > 8.0) was observed, driven by protonation-induced resonance changes. Computational studies, including Frontier Molecular Orbital (FMO) analysis, revealed a Highest Occupied Molecular Orbital (HOMO)-Lowest Unoccupied Molecular Orbital (LUMO) gap of 1.94 eV, indicating efficient electronic transitions critical for its color properties. Molecular Electrostatic Potential (MEP) and Fukui function analyses provided further insights into the dye's reactivity and potential applications. The dyeing properties were rigorously assessed through K/S values, CIELAB color space, and fastness properties on cotton fabric, demonstrating varied color depths and hues influenced by different mordants, with copper and manganese significantly enhancing color intensity. Colorfastness tests revealed good to fair durability, with untreated fabrics showing optimal performance. This thorough characterization underscores the promising potential of this newly synthesized azo dye for applications in pH-responsive textiles and functional materials, highlighting its relevance for advanced textile and material science applications.

FT-IR, UV–Vis, density functional theory and molecular docking studies on 3,7,11,15-Tetramethyl-2hexadecen-1-ol

The organic molecule of 3,7,11,15-Tetramethyl-2-hexadecen-1-ol is frequently present in plant chlorophyll pigment. The title compound possesses antimicrobial, antibacterial, antioxidant, anti-inflammatory, and anticancer characteristics. The 3TMH molecule are being investigated using Gas Chromatography Mass Spectrometry (GC–MS) analysis, Ultraviolet-Visible (UV–Vis), Fourier Transform Infrared Spectroscopy (FT-IR), and Density Functional Theory (DFT) approach with the Becke,3-parameter, Lee–Yang–Parr (B3LYP) method, 6–311++G (d, p) basis set is used to analyse the geometrical parameters, Highest Occupied Molecular Orbital and the Lowest Unoccupied Molecular Orbital (HOMO-LUMO), and Molecular Electrostatic Potential (MEP) mapping. In the 3TMH molecules, the computed Natural Bond Orbital (NBO) analysis exhibit the high stabilization interaction (intra-inter, hydrogen bonding, and charge delocalization) between the donor and acceptor. The UV–Vis spectra of the maximum absorption correlated with different solvents as determined by Time-Dependent Density Functional Theory (TD-DFT). According to Veda 04, the measured FT-IR spectrum and the theoretical spectra of vibrational assignment with Potential energy distribution (PED%) are in good agreement. The Electron Localization Function (ELF) and Localized Orbital Locator (LOL) mapping has provided an explanation for the chemical bonding within fragments, as well as interactions between the atoms. The strong attraction, strong repulsion, and weak interaction have been estimated Reduced Density Gradient (RDG). Furthermore, the molecular docking examined ligand-protein interaction of least binding energy 6.73 kcal/mol against anti-cancer activity.

Synthesis, spectroscopic analysis, molecular docking and DFT study of some new heterocyclic compounds tethered 4‑hydroxy-1-methylquinoline-2(1H)one

A diversity of heterocyclic compounds (3, 6–8, 9, 11 and 12) linked 4‑hydroxy-1-methylquinoline-2(1H)one moiety have been synthesized from ring opening ring closure reaction (RORC) of 4‑hydroxy-6-methyl-3-nitro-2H-pyrano[3,2-c]quinoline-2,5(6H)‑dione (2) with various nucleophilic reagents namely hydrazine hydrate, phenylhydrazine, 3-hydrazino-5,6-diphenyl-1,2,4-triazine (4), 7‑chloro-4-hydrazino quinoline (5), 3-amino-1,2,4-triazole, 2-aminobenzimidazole and 3-amino-4,6-dimethyl-1H-pyrazolo[3,4-b]pyridine (10). The biological efficiency of the synthesized compounds against hepatocellular carcinoma cell lines (HepG-2) was analyzed both experimentally and theoretically (topoisomerase IIβ protein). Compound 12 (IC50=4.36 µM/L) has the highest anticancer activity against HepG-2 cell lines in comparison with the positive control (Cis-platin). The synthesized compounds were optimized by DFT/B3LYP functionality using the 6–311G++(d,p) basis set. Frontier molecular orbital analysis using global reactivity parameters indicated that compounds 1 and 12 have the largest) ∆E = 4.268 eV) and smallest) ∆E = 3.344 eV) energy gap, respectively. Thus, compound 1 (η= 2.134 eV) is harder than other compounds and has high stability. While compound 12 (S = 0.598eV-1) is softer than other compounds and more reactive. MEP surface and Fukui function were used to show charge distribution and show reactive zones within the molecules. For further validate of the NMR results, GIAO method was utilized to evaluation the 1HNMR and 13CNMR chemical shifts which were then correlate with the experimental spectra. Non-linear optical (NLO) behavior was further studied and compared to urea, which is a prototype substrate, and found to be greater than that of urea. Swiss-ADME (absorption, distribution, metabolism and excretion) analysis was performed to examine the drug-likeness properties of the current compounds. Finally, using the topoisomerase IIβ protein (PDB ID: 4G0U) receptor, molecular docking studies were used to examine the binding interactions of the synthesized compounds and correlated with anticancer activity.

Synthesis, crystal structure, Hirshfeld surface analysis, DFT studies and biological evaluation of bis(acetonitrile)bromido(η6-1-isopropyl-4-methylbenzene)osmium(II) hexafluoroantimonate

The complex bis(acetonitrile)bromido(η6-1-isopropyl-4-methylbenzene)osmium(II) hexafluoroantimonate, [OsBr(C10H14)(CH3CN)2]SbF6 (1) crystallizes as a triclinic system in space group P1 (no. 2), consisting of two cationic osmium(II) complex ions and two anionic hexafluoroantimonate counterions in each cell. Density Functional Theory (DFT) calculations were performed at the B3LYP/LanL2DZ and B3LYP/Def2 − SVP/Def2 − TZVP levels of theory. Reactivity descriptors and charge transfer properties were computed using frontier molecular orbital analysis. The DFT-optimized model systems from both basis sets were comparable to the experimentally determined X-ray diffraction results. Hirshfeld surface analysis shows significant non-covalent interactions including hydrogen bonds and halogen interactions. The MTT technique was utilized to conduct an in vitro cytotoxicity assay of 1 against cancerous cell lines (MCF-7 and A549) and normal cells (HEK293). Complex 1 is potent towards cancer cells as evidenced by the IC50 values of 5.02 ± 0.05 µM for MCF-7 cells and 13.36 ± 0.04 µM for A549 cells. Complex 1 demonstrated lower toxicity to normal cells with an IC50 value of 26.76 ± 0.08 µM for the HEK293 cell line compared to the doxorubicin standard with an IC50 value of 1.2 ± 0.1 µM.

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).

Theoretical Insights into Regulation of Red/Blue-Shifting Hydrogen Bonds Through Cooperativity with Regium Bonds.

To deeply understand the characteristics and regulation of red/blue-shifting hydrogen bonds (HBs), a theoretical investigation was conducted to explore the cooperativity between regium bonds and HBs in the complexes of Y···MCN···HCX3 (M = Cu, Ag, Au; Y = H2O, HCN, NH3; X = F, Cl). When MCN formed a hydrogen bonding dimer with CHF3 or CHCl3, the blue shift of C-H vibration frequency v(C-H) decreases as the following sequence Au > Cu > Ag, and the red shift decreases following the order Ag > Cu > Au. Upon the formation of ternary complexes, the presence of regium bonding interactions exerts a positive synergistic effect, resulting in the strengthening of the HBs. This, in turn, leads to noticeable changes in the red and blue shifts of v(C-H). In CHF3 complexes, v(C-H) undergoes a decrease in the blue shift, whereas that in CHCl3 exhibits an increase in the red shift. Especially, a transition from blue to red shift is observed within the AuCN···HCCl3 complex. As the strength of the regium bond increases, the trend of shifting from blue to red becomes more pronounced. For a given MCN, the changes occur in the order of NH3 > HCN > H2O. The interplay between two interactions was revealed by the molecular electrostatic potentials (MEP), the atoms in the molecule (AIM), and natural bond orbitals (NBO) analysis. It is revealed that Δv(C-H) is linearly correlated with a series of configuration and energy parameters. We explain the red- and blue-shifting HBs and their changes from the perspective of hyperconjugation and rehybridization. The presence of the positive synergistic effect enhances the hyperconjugation effect, thereby leading to a reduction in the blue shift and an increase in the red shift of v(C-H) within the complexes. This study enriches previous mechanisms regarding red- and blue-shifting HBs and introduces a novel idea to manipulate the characteristics of HBs, with the potential to impact the functioning of intricate systems.

Computational Study of the Kinetics and Mechanisms of Gas-Phase Decomposition of N-Diacetamides Using Density Functional Theory.

In this research work, we examined the decomposition mechanisms of N-substituted diacetamides. We focused on the substituent effect on the nitrogen lone-pair electron delocalization, with electron-withdrawing and electron donor groups. DFT functionals used the following: B1LYP, B3PW91, CAMB3LYP, LC-BLYP, and X3LYP. Dispersion corrections (d3bj) with Becke-Johnson damping were applied when necessary to improve non-covalent interactions in the transition state. Pople basis sets with higher angular moments and def2-TZVP basis sets were also applied and were crucial for obtaining consistent thermodynamic parameters. The proposed mechanism involves a six-membered transition state with the extraction of an α hydrogen. Several conformers of N-diacetamides were used to account for the decrease in entropy in the transition state in the rate-determining state. All calculations, including natural bond orbital (NBO) analyses, were performed using the Gaussian16 computational package and its GaussView 6.0 visualizer, along with VMD and GNUPLOT software. The isosurfaces and IBSIs were calculated using MultiWFN and IGMPlot, respectively.

Density functional theory guide for copolymerization mechanism between allyl radical with radicalophile: photo-driven radical mediated [3 + 2] cyclization.

The challenge of activating inert allyl monomers for polymerization has persisted, prompting our proposal of the photo-driven radical mediated [3 + 2] cyclization reaction (PRMC). This innovative approach significantly expedites the homopolymerization of multi-allyl monomers, enabling the synthesis of embolic microspheres for hepatocellular carcinoma interventions. PRMC involves allyl monomers to form allylic radicals and then radicals participating in a cycloaddition reaction with unsaturated olefins as radicalophiles to form cyclopentane-based radical products. While extensively studied in the theoretical and experimental homopolymerization, PRMC's application in copolymerization remains unexplored. To address this knowledge gap, we explored the elementary reaction, selecting allyl methyl ether radicals (AMER) and α,β-unsaturated ketones as radicalophiles for copolymerization investigations by density functional theory (DFT) analysis. We quantified energy differences between ground and excited states of reactants, elucidated frontier molecular orbitals, and assessed thermodynamic data for copolymerization feasibility. We also evaluated the electronic properties of reactants, predicting the reactivity of radicalophiles and the interactions of intermolecular reactions. Additionally, we applied transition state theory and interaction/deformation models and conducted a local orbital analysis to comprehensively study excess electron distribution and gyration radius of cyclic radical product. Our findings offer vital insights into PRMC's potential in copolymerization. This research provides a robust theoretical foundation for practical application, enhancing the polymerization field. Based on density functional theory (DFT), the calculations were performed at the M06-2X/6-311 + + G(d,p) level in/by Gaussian 16 package. Subsequently, our analytical results apply time-dependent density-functional theory (TD-DFT) and solvent modeling (SMD). Single-point energy calculations determine the driving force behind the radicals' reaction with radicalophiles. Furthermore, we assessed the electrostatic potential (ESP) of the reactants. The results of the calculations were visualized by the Multiwfn 3.6 and VMD 1.9 programs.

A DFT study of eugenol adsorption onto pure and Si-doped Al12N12 and B12N12 fullerene-like nanocages

Density functional theory (DFT) methods have been employed in this work to study the adsorption behavior of eugenol (Eug) on the external surface of pure and Si-doped Al12N12 and B12N12 fullerene-like nanocages. All calculations were performed using the M062X-D3 functional combined with the 6-311 + G(d,p) basic sets. In order to probe the reliability of the DFT method, three other functionals (B3LYP-D3, CB3LYP-D3 and WB97XD) were employed and no significant difference was observed in the adsorption energy values of the most stable configurations (AEII and BEII). Also, the complexes are found to be stable in standard conditions in gas and aqueous phases, and the adsorption process is found to be exothermic and spontaneous. Interestingly, Si-doped nanomaterials (Si-AEII and Si-BEII) form the most stable adsorbent-adsorate molecular states (Eads = −90.07 and −61.42 kcal/mol respectively) in gas phase. Furthermore, Si-AEII and Si-BEII complexes exhibit the highest reactivity, characterized by the lowest values of the HOMO-LUMO energy gap (5.50 and 7.07 eV respectively). MEP map of the studied systems showed electron rich and electron deficient sites. Natural bond orbital analyses revealed that the interaction of Al12N12 with Eug is mainly due to the strong electron delocalization LP(2)O10 → LP*(2)Al47 (E(2) = 34 kcal/mol), whereas in Eug-B12N12 complex, it is mainly due to the electron delocalization LP(2)O10 → P*(4)B36 (E(2) = 96.53 kcal/mol). The QTAIM analysis revealed that Si–O and Al–C/B–C bonds linking eugenol to doped cages are attractive weak interactions and their nature have been confirmed via RDG/NCI analyses. Indeed, the present study revealed the suitability of Si-doped Al12N12 and B12N12 fullerene-like nanocages for the efficient drug delivery of eugenol.

Novel Trifunctional Intramolecular Frustrated Lewis Pair Derived From Aminoboronic Acid for Converting CO2 Into Valuable Chemicals

ABSTRACTThe conversion of CO2 into valuable chemicals remains a significant challenge for achieving environmental sustainability, primarily due to the stability of the CO2 molecule. This necessitates the development of efficient and ecofriendly catalysts. In recent years, frustrated Lewis pairs (FLPs) have shown promise for CO2 utilization. In this study, we introduce α‐aminodiboronic acid (DBA), a novel trifunctional aminoboronic acid, as an intramolecular FLP for converting CO2 into cyclic carbonate and formic acid. Using density functional theory (DFT) calculations, we explored the reaction mechanism and investigated DBA's electronic structure through molecular electrostatic potential surface (MESP) and natural bond orbital (NBO) analyses. Our results reveal that one −B (OH)2 group induces an unusual state of frustration in the molecule due to charge transfer from the nitrogen atom's lone pair to the π* orbitals, enhancing catalytic performance. The additional −B (OH)2 group serves as an anchoring site for reactive species. The epoxide activation energy is reduced by approximately 27 kcal/mol compared to the uncatalyzed reaction, and the reduction of CO2 occurs with a requirement of 26 kcal/mol. The additional −B (OH)2 plays a crucial role in the catalytic mechanism and minimizes the energies of various structures observed in the reaction path. The reaction energetics align with structural analysis observations, marking this study as the first report on single‐molecule trifunctional FLPs for transforming CO2 into valuable chemicals.

Vibrational spectra of second generation antidiabetic drug gliquidone exhibiting anticancer activity, antioxidant activity using both the experimental and theoretical approach

The prevalence of diabetes mellitus in world is hundreds of millions and still skyrocketing. Diabetes mellitus damages the entire vital system and leads to a mortality rate and it is a serious threat to human life. It is high time to develop an effective drug with desired and selective characteristics. GQD is a second generation FDA approved drug that evokes current research interest owing to its pharmaceutical application, such as antidiabetic activity, which is utilized to treat type 2 diabetes mellitus. An efficient approach for examining the physicochemical properties of the drug is Density Function Theory (DFT). Optimization of GQD has been carried out with the help of Becke 3- parameter Lee Yan Parr with 6–311 G** basis set. Stability, intramolecular interaction, intermolecular interaction, hyperconjugation, and delocalization of the system have been analysed using the Natural Bond Orbital (NBO) analysis. GQD has been subjected to FTIR and FT-Raman characterization, and MOLVIB 7 software has been utilized to assign the normal modes of vibrations. Frontier molecular study reveals a small energy gap, and this predicts the molecule to be more reactive. The molecular Electrostatic Potential (MEP) mapped surface shows the potential binding site, and this is responsible for the pharmaceutical activities. Mulliken population and Natural population analysis show the reactive sites of the molecule. GQD has been tested as a promising molecule with antioxidant and anticancer activity.

Development of pivalic acid conjugated Nafion modified glassy carbon electrode for sensitive detection of Cu(II) by electrochemical approach

In this work, pivalic acid (pivH) molecule is employed for an electrochemical sensing of copper cations in an aqueous medium. For sensitive as well as selective potential sensor application, pivH was fabricated onto a glassy carbon electrode (GCE) facilitated by adhesive conducting binder, nafion, so as make it selective and effective electrochemical probe (pivH/Nafion/GCE) towards specific heavy metal cations. This newly fabricated pivH/Nafion/GCE reveals enhance electrochemical activity toward copper ions in the presence of other interfering heavy metal cations in phosphate buffer solution (PBS) of pH=7. The calibration plot was linear (r2 = 0.9879) across broad linear dynamic range (LDR) spanning Cu2+ concentration from 0.1 nM to 0.01 M. The sensitivity and detection limit was found to be 0.0212 × 10−2 µAµM−1cm−2 and 0.014 nM, respectively. So, this newly fabricated GCE as selective electrochemical probe offers a sensitive as well as selective detection of Cu2+ cations in real environmental samples using a novel electrochemical, current–potential (I-V), approach, for the first time. Further, we explored pivalic acid for the preparation of new di-nuclear copper complex, [Cu2(piv)4(pivH)2] (where piv = pivalate; pivH=pivalic acid) and characterized by Fourier transform infrared spectroscopy (FTIR) spectroscopy, elemental analysis and single crystal X-ray diffractometry. Density functional theory (DFT) calculations were carried out to confirm the interactions and these calculations well-support to experimental data. In case of deprotonated form of pivH, Molecular Electrostatic Potential (MEP) analysis exhibits electrostatic potential equals to −148.4 kcal/mol which suggest about the strong interaction of –COOH with copper centers. Similarly, interaction energies, the quantum theory of atoms in molecules (QTAIM) study and Natural Bond Orbital (NBO) analysis also favor to experimental work. Thus, this novel study demonstrates an excellent approach for highly selective and sensitive detection of Cu2+ cations in short response time with low detection limit and good reproducibility by using I-V method based on newly designed pivH/Nafion/GCE as selective Cu2+ cationic electrochemical sensor. The experimental data was compactable with theoretical calculations.

Study of chemical reactivity and molecular interactions of the hydrochlorothiazide-4-aminobenzoic acid cocrystal using spectroscopic and quantum chemical approaches

In this study, the molecular, electronic, and chemical properties of the drug hydrochlorothiazide (HCTZ) are determined after cocrystallization with 4-aminobenzoic acid (4-ABA). Analysis has been performed to understand how those variations lead to alteration of physical properties and chemical reactivity in the cocrystal HCTZ-4ABA. IR and Raman characterizations were performed along with quantum chemical calculations. A theoretical investigation of hydrogen bonding interactions in HCTZ-4ABA has been conducted using two functionals: B3LYP and wB97X-D. The results obtained by B3LYP and wB97X-D are compared which leads to the conclusion that B3LYP is the best applied function (density functional theory) to obtain suitable results for spectroscopy. The chemical reactivity descriptors are used to understand various aspects of pharmaceutical properties. Natural bond orbital (NBO) analysis and quantum theory of atoms (QTAIM) are used to analyze nature and strength of hydrogen bonding in HCTZ-4ABA. QTAIM analyzed moderate role of hydrogen bonding interactions in HCTZ-4ABA. The calculated HOMO-LUMO energy gap shows that HCTZ-4ABA is chemically more active than HCTZ drug. These chemical parameters suggest that HCTZ-4ABA is chemically more reactive and softer than HCTZ. The results of this study suggest that cocrystals can be a good alternative for enhancing physicochemical properties of a drug without altering its therapeutic properties.

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.

β-d-Glucopyranose – Silver+ (1:1) complex assisted aromaticity involving electron deficient X3 (X=Be, Mg) core

Seeing the frontier molecular orbitals (FMO) picture of β-d-glucopyranose–silver+ (1:1) complex ([Ag(C6H12O6)]+) reported in a recent article (Mondal, 2024) [53], we used the FMO based approach to obtain inverted sandwich like organometallic complex comprising X3 (X=Be, Mg) core, in silico. Thermodynamic feasibility of obtaining [(C6H12O6)Ag-X3-Ag(C6H12O6)] (X=Be, Mg) complexes are explored. Conceptual density functional theory (CDFT) based reactivity descriptors guide to ascertain the stability order of such complexes. By the help of natural bond orbital analysis, Wiberg bond indices (WBI), bond critical point analysis, electron density descriptors, and gradient isosurface between selected contacts, the nature of interaction between the X3 core and Ag metals are studied. FMO of the complexes further help in ascertaining the nature of binding. Energy decomposition analysis marks the interaction between X3 and Ag metals in [(C6H12O6)Ag-X3-Ag(C6H12O6)] (X=Be, Mg) as partially covalent. Negative values of nucleus independent chemical shift (NICS) at the triangular ring (X3) centres [NICS(0)] indicate aromatic property.

Structural evolution, electronic and optical properties of praseodymium doped silicon cluster PrSin0/- (n = 10–20): A theoretical investigation

The rare earth dope d nano-cluster can be a building block for the next-generation photo-electrical industry, so the imminent discovery of novel, suitable nano-functional material is urgent. Praseodymium element as a wonderful dopant, bestow a novel photoelectrochemical properties for nanomaterials especially for semiconductor, derived from its unfulfilled 4f electrons configuration and active electronic transitions between 4f to 4f and 4f to 5d. In view of this, the neutral and anionic clusters of PrSin0/- with a medium size of n = 10–20 are comprehensively investigated by the quantum chemistry method of mPW2PLYP associated with the global searching potential energy surface techniques. The geometry evolution in medium size for PrSin can be attributed to three stages of replaced (n = 10–12), linked (n = 13–19), and cage (n = 20) structure. For PrSin-, two evolution phases are obviously observed by linked (n = 10–19) and cage (n = 20) structure. The PES spectra of the anionic most stable cluster and several degeneracy structures are simulated to identify the ground state structure. Each cluster of AEA, charge transfer, and VDE values are all calculated. Combined with binding energy, HOMO-LUMO gap, molecular orbital analysis, and a series of optical properties estimated, including simulated UV–vis, IR, and Raman spectra, excitation behavior shows PrSi20- has not only prominent stability but also has a proper range of lighting absorption, higher electron-hole recombination, possible as a functional material for optoelectronic devices.

DFT studies on the performance of BN nanocage (B12N12) as adsorbent and sensor for fosfomycin

The investigation focused on exploring the potential applications of the BN nanocage (B12N12) as both an adsorbent and a sensor for removing and detecting fosfomycin (FM) using density functional theory computations. In this respect, the interaction of FM with B12N12 was evaluated at 3 different configurations and the most stable one was determined. The results showcased the interaction between FM and B12N12, highlighting the feasibility, exothermic nature, and spontaneity of the interaction, emphasizing the effectiveness of B12N12 as an FM adsorbent. Moreover, the study scrutinized the influence of water as a solvent and different temperatures on the thermodynamic parameters. Interestingly, the results indicated that these factors had negligible impacts on the interactions. Nonetheless, it was noted that the interactions were a bit stronger in vacuum and at lower temperatures. Additionally, the Frontier Molecular Orbital (FMO) analysis exhibited a bandgap of 6.716 eV for B12N12, which increased by approximately 90 % to 13.381 eV upon FM adsorption, indicating a significant reduction in the electrochemical conductivity of BN nanocage during the FM adsorption process, thereby hinting at its potential use as an analytical signal for the electrochemical detection of FM.