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This study explores the interactions between hexanal Schiff bases and a B12N12 nanocage, employing density functional theory (DFT) calculations to deepen our understanding of noncovalent bonds. Hexanal, a key component in tea, plays a vital role in prolonging the shelf-life of various plant-based products by inhibiting phospholipase-D. Our research initially focused on synthesizing Schiff bases through the condensation of hexanal with nucleobases and an amino acid. We then conducted a series of DFT calculations, including geometry optimizations, frontier molecular orbital (FMO), natural bond orbital (NBO) and noncovalent interactions (NCI) assays, using Gaussian 16 and ORCA 5.0.2 software packages. This study reveals that hexanal Schiff bases form stable complexes with the B12N12 nanocage, exhibiting notable dative coordinate bonding. The FMO analysis indicates a significant energy gap variation among the complexes, with CSB2 showing the lowest energy gap, hinting at its high reactivity. In the LED assay, CSB2 demonstrates the lowest decomposition energy, highlighting its potential stability. The AIMD simulations provide insights into the electronic motions of these complexes, underscoring their dynamic nature. Our NBO analysis offers a comprehensive view of the electron distribution within these complexes, emphasizing the significance of nitrogen and boron atoms in the bonding process. The NCI assay sheds light on the predominant van der Waals and steric interactions contributing to the stability of the complexes. This investigation provides a detailed account of the NCI between hexanal Schiff bases and the B12N12 nanocage. The findings not only contribute to the field of noncovalent bonding in inorganic- fullerene structures but also open avenues for future applications in material science and molecular engineering. [ABSTRACT FROM AUTHOR]

Using a 1:1 cocrystal of (E)‐N‐(3,4‐difluorophenyl)‐1‐(pyridin‐4‐yl)methanimine with acetic acid, C12H8F2N2·C2H4O2, we investigate the influence of F atoms introduced to the aromatic ring on promoting π–π interactions. The cocrystal crystallizes in the triclinic space group P1. Through crystallographic analysis and computational studies, we reveal the molecular arrangement within this cocrystal, demonstrating the presence of hydrogen bonding between the acetic acid molecule and the pyridyl group, along with π–π interactions between the aromatic rings. Our findings highlight the importance of F atoms in promoting π–π interactions without necessitating full halogenation of the aromatic ring. [ABSTRACT FROM AUTHOR]

Observational data show complex organic molecules in the interstellar medium (ISM). Hydrogenation of small unsaturated carbon double bond could be one way for molecular complexification. It is important to understand how such reactivity occurs in the very cold and low‐pressure ISM. Yet, there is water ice in the ISM, either as grain or as mantle around grains. Therefore, the addition of atomic hydrogen on double‐bonded carbon in a series of seven molecules have been studied and it was found that water catalyzes this reaction. The origin of the catalysis is a weak charge transfer between the π MO of the unsaturated molecule and H atom, allowing a stabilizing interaction with H2O. This mechanism is rationalized using the non‐covalent interaction and the quantum theory of atoms in molecules approaches. [ABSTRACT FROM AUTHOR]

A novel triazole derivative was synthesized and characterized by various spectroscopic techniques such as FTIR, NMR and single crystal X-ray diffraction study. The title compound crystallizes in the triclinic space group P 1 ¯ and exhibits inter-molecular hydrogen bonds of the type C–H...O and C–H...N. Hirshfeld surface analysis shows that the major intermolecular interaction is mainly due to H...H contacts. DFT calculations were performed to study their electronic properties. QTAIM and NCI studies were used to investigate the weak interactions in five triazole derivatives including the title compound. [ABSTRACT FROM AUTHOR]

Developing highly effective nonlinear optical (NLO) materials is a cutting-edge field of study. The desirability of promising NLO materials for optoelectronic and electronic applications drove us to investigate the sulflower (C18S9) doped complexes for developing highly efficient NLO materials. A successful computational design technique for superhalogens (BeF3, MgF3, CaF3, CaCl3) doping is employed on sulflower, and eight stable isomers (BeF3@SF-5M, BeF3@SF-9M, MgF3@SF-5M, MgF3@SF-9M, CaF3@SF-5M, CaF3@SF-9M, CaCl3@ SF-5M, CaCl3@SF-9M) are proposed for NLO properties. DFT and TD-DFT simulations confirm the potential use of superhalogen-doped sulflower complexes for NLO response applications by evaluating NLO response properties, photophysical aspects, frontier molecular orbital (FMO), natural bond orbitals (NBO), non-covalent interaction (NCI), vertical ionization energies (VIE), interaction energies (Eint), molecular electrostatic potential (MEP) and density of state (DOS) analysis. The Eint (−28.37 to −53.86 kcal/mol) and VIE (7.0-7.4 eV) findings suggest that superhalogens-doped sulflower complexes are thermodynamically stable and show durable interaction among sulflower and doped superhalogens. Superhalogens doping on sulflower effectively shorten the energy gap from 4.46 eV (pure sulflower) to 4.17 eV in CaCl3@SF-5M isomer. Superhalogens doping causes a change in the dipole moment from 0 D of pure sulflower to 12.57 D in the CaCl3@SF-5M isomer. Proficient intermolecular charge transfers between sulflower and doped superhalogens were established by NCI and NBO analyses. UV-Vis investigation revealed that all superhalogen-doped sulflower complexes are adequately transparent in the near-infrared and visible wavelength ranges. Augmentation in polarizability value from 333.86 a.u.−569.98 a.u and in first hyperpolarizability from 0.00 a.u to 6.6 × 104 a.u. is achieved upon superhalogens doping. A striking NLO response (β0 = 6.6 × 104 a.u) is exhibited by CaCl3@SF-5M isomer. This report provides an efficient superhalogens doping technique for creating highly effective future NLO systems and recommends superhalogens-doped sulflower complexes as ideal entrants for future NLO applications. [ABSTRACT FROM AUTHOR]

The computational simulations of nonlinear optical (NLO) characteristics of silver (Ag) and alkaline earth metals (Be, Mg, and Ca) doped 15-crown-5 (15C5) complexes are the focus of this research. By accurately grabbing hypothetical computations, DFT and TD-DFT approached in-depth characterization of M(Ag@15C5) where (M = Be, Mg, and Ca) is achieved using WB97XD functional along with LANL2DZ basis set. The consequences of different analyses like FMOs (frontier molecular orbitals), hyperpolarizabilities, DOS (density of states), interaction energy (Eint), absorption maximum (λ max), dipole moment (μ ), TDM (transition density matrix), EDDM (electron density distribution map), electrostatic potential (ESP), and electrical conductivity (σ ) were investigated for pure surface 15C5 and all the doped complexes. NCI analysis was performed to study the nature of interaction between surface and dopants. The doping method for all complexes admirably improved charge transfer properties like enhanced λ max lie in the range of 332–491 nm with narrowing band gap (Eg) in the range of 3.28–3.78 eV in comparison to pure 15C5 with Eg of 4.76 eV and 132 nm λ max. Complexes Be(Ag@15C5), Mg(Ag@15C5), and Ca(Ag@15C5) showed a significant increase in linear polarizability (α o) and first hyperpolarizability ( β o ) due to the lowest excitation energies of these complexes as compared to pure 15C5. All these outcomes of mentioned systems revealed that these complexes can be used as efficient and promising NLO materials. [ABSTRACT FROM AUTHOR]

The polyethylene (PE) and polypropylene (PP) microplastics (MPs) can act as carriers of the molecule 3-tertiary-butyl-4-hydroxyanisole (3BHA), which propose harmful impacts to aqueous ecosystems. Meanwhile, 3BHA has already been detected in several environments and human urine and serum samples. 3BHA is an antioxidant in foods, food packaging, cosmetics and pharmaceuticals. However, it raised concerns about its possible endocrine-disrupting effect in recent years. The interaction between two MPs and 3BHA could start in farmland and be maintained during transportation to the ocean. Herein, the adsorption behavior and mechanism of 3BHA by PE and PP MPs were investigated via molecular dynamics (MD) simulation, density functional theory (DFT), non-covalent interactions (NCI), the total density of states (TDOS) and frontier molecular orbital (FMO). Furthermore, the stability of 3BHA adsorbed complexes was investigated by adsorption-free energies (ΔGads), showing that the 3BHA has a significant interaction with the MPs studied, with energies of -1.31 kcal mol−1 and − 4.19 kcal mol−1 for PE and PP, respectively. Intermolecular van der Waals forces were one of the primary adsorption mechanisms of 3BHA by MPs, as evidenced by NCI calculations. It was demonstrated that the adsorption of the 3BHA in MPs decreases the energy gap (Eg) of the HOMO and LUMO orbitals; for PE MP, the Eg decreases from 12.8386 to 9.1445 eV, and from 12.7957 to 9.2092 eV for PP MP. The adsorption of the 3BHA on the MPs resulted in an increase in the TDOS distribution and a slight shift in the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) states. In conclusion, this study about the mechanism of adsorption of the 3BHA in PE and PP MPs can provide new evidence and enhance our understanding of the environmental behavior of 3BHA in the environment. [ABSTRACT FROM AUTHOR]

Two new coordination compounds comprising Mn(II) and Cu(II) viz. [Mn(bz)2(Hdmpz)2(H2O)] (1) and [Cu(crot)2(Hdmpz)2] (2) (where, bz = benzoate; crot = crotonate; Hdmpz = 3, 5-dimethyl pyrazole) were synthesized and characterized. The characterization involved a single crystal X-ray diffraction technique, FT-IR spectroscopy, electronic spectroscopy, TGA, and elemental analyses. Compounds 1 and 2 crystallize as mononuclear entities of Hdmpz with penta-coordinated Mn(II) and hexa-coordinated Cu(II), respectively. These complexes exhibit distorted trigonal bipyramidal and distorted octahedral geometries, respectively. A crystal structure analysis of compound 1 elucidates the existence of C–H⋯π and π-stacking interactions alongside O–H⋯O, N–H⋯O, and C–H⋯O H-bonding interactions contributing to the stabilization of the compound's layered assembly. Similarly, in compound 2, the crystal structure stability is attributed to the presence of hydrogen bonding in conjugation with π-stacking interactions. We conducted theoretical investigations to analyze π⋯π, H-bonding, and antiparallel CH···π non-covalent interactions observed in compounds 1 and 2. DFT calculations were performed to find out the strength of these interactions energetically. Moreover, QTAIM and non-covalent interaction (NCI) plot index theoretical tools were employed to characterize them and evaluate the contribution of the H-bonds. [ABSTRACT FROM AUTHOR]

An international consensus report in 2019 recommended a classification system for limbic-predominant age-related TDP-43 encephalopathy neuropathologic changes (LATE-NC). The suggested neuropathologic staging system and nomenclature have proven useful for autopsy practice and dementia research. However, some issues remain unresolved, such as cases with unusual features that do not fit with current diagnostic categories. The goal of this report is to update the neuropathologic criteria for the diagnosis and staging of LATE-NC, based primarily on published data. We provide practical suggestions about how to integrate available genetic information and comorbid pathologies [e.g., Alzheimer's disease neuropathologic changes (ADNC) and Lewy body disease]. We also describe recent research findings that have enabled more precise guidance on how to differentiate LATE-NC from other subtypes of TDP-43 pathology [e.g., frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS)], and how to render diagnoses in unusual situations in which TDP-43 pathology does not follow the staging scheme proposed in 2019. Specific recommendations are also made on when not to apply this diagnostic term based on current knowledge. Neuroanatomical regions of interest in LATE-NC are described in detail and the implications for TDP-43 immunohistochemical results are specified more precisely. We also highlight questions that remain unresolved and areas needing additional study. In summary, the current work lays out a number of recommendations to improve the precision of LATE-NC staging based on published reports and diagnostic experience.

Theoretical evaluation of gallium nano-clusters decorated with certain metalloids (B, Si and Ge) ( Ga 1 2 X 1 2 , where X = N, O) as proficient adsorbents for 2,4-dichloropropionic acid (Dal) was conducted using the DFT/ ω B97X-D functional with a 6-311++G(d,p) basis set. Notably, the Ga 1 2 O 1 2 -decorated nano-structures demonstrated superior efficiency compared to their Ga 1 2 N 1 2 counterparts. In the analysis of electronic structure, Ga@Si_Dal (GS2) exhibited a narrow band gap of 3.237 eV between the conduction and valence bands, signifying heightened system conductivity. For the adsorption system, Ga@Si_Dal (GS2) displayed an adsorption distance of 2.45400 Å, with the most stable optimal value of −2159.31 upon Dal adsorption. GaN@B_Dal (B1) exhibited the shortest bond length at 1.267 Å. The computed adsorption energy values for comparative assessment were universally negative, indicating robust interaction between adsorbent and adsorbate. GaO@Ge_Dal (GG2) boasted the most negative adsorption energy at −4.811 kcal/mol when compared with other decorated surfaces. The study underscored GaO@Si_Dal (GS2) as possessing a more potent non-covalent interaction than other adorned surfaces, as substantiated by its higher electron density and Laplacian of electron density. This research offers valuable insights for both researchers and industrialists engaged in combating environmental pollution. Theoretical evaluation of gallium nano-clusters decorated with certain metalloids (B, Si, and Ge) ( Ga 1 2 X 1 2 , where X = N, O) as proficient adsorbents for 2,4-dichloropropionic acid (Dal) was conducted using the DFT/ ω B97X-D functional with a 6-311++G(d,p) basis set. [ABSTRACT FROM AUTHOR]

A new class of benzimidazole-based derivatives (4a–j, 5, and 6) with potential dual inhibition of EGFR and BRAFV600E has been developed. The newly synthesized compounds were submitted for testing for antiproliferative activity against the NCI-60 cell line. All newly synthesized compounds 4a–j, 5, and 6 were selected for testing against a panel of sixty cancer cell lines at a single concentration of 10 µM. Some compounds tested demonstrated remarkable antiproliferative activity against the cell lines tested. Compounds 4c, 4e, and 4g were chosen for five-dose testing against 60 human tumor cell lines. Compound 4c demonstrated strong selectivity against the leukemia subpanel, with a selectivity ratio of 5.96 at the GI50 level. The most effective in vitro anti-cancer assay derivatives (4c, 4d, 4e, 4g, and 4h) were tested for EGFR and BRAFV600E inhibition as potential targets for antiproliferative action. The results revealed that compounds 4c and 4e have significant antiproliferative activity as dual EGFR/BRAFV600E inhibitors. Compounds 4c and 4e induced apoptosis by increasing caspase-3, caspase-8, and Bax levels while decreasing the anti-apoptotic Bcl2 protein. Moreover, molecular docking studies confirmed the potential of compounds 4c and 4e to act as dual EGFR/BRAFV600E inhibitors. [ABSTRACT FROM AUTHOR]

The detection of toxic molecules has gained imperial attention to protect living organisms and their environment. The broadly explored sensor behaviour of triazine-based C3N4 reveals their ultra-high sensitivity towards numerous toxic molecules e.g., chemical welfare agents. However, another potential analogue of C3N4 composed of heptazine exhibits remarkable electrical and optical properties but has not been much explored in sensor technology, especially for toxic pollutants. Keeping this in mind, the sensing performance of heptazine-based g-C3N4 is explored for the detection of toxic amides by using First Principles calculations. In this context, acryloyl amide (C2H3CONH2), acryloyl chloride (C2H3COCl), fluoroacetic acid (C2H3FCOOH), flouroaceta amide (C2H2FONH2), flouroacetyl chloride (C2H2FOCl) are selected as toxic pollutants; herein, for the ease of understanding, these molecules are represented as AAM, ACl, FAAc, FAA, & FACl, respectively. The electrochemical sensitivity of g-C3N4 is determined via geometric, energetic, and electronic properties analysis, whereas the photochemical sensitivity is explored by UV–Vis absorption analysis based on TD-DFT calculations. The interaction energies of studied molecules on C3N4 range between − 9.09 and - 23.39 kcal/mol depending upon the type of interactions e.g., hydrogen bonding or dispersion, which are explained on the basis of Symmetry Adopted Perturbation Theory, Non-Covalent Interaction Index, and Quantum Theory of Atoms in Molecules analyses. The density of State analysis, Frontier Molecular Orbitals and NBO charge transfer characterized that the electronic behaviour of g-C3N4 can be an effective sensor material with a semiconducting nature and significant charge transfer. Lastly, UV–Vis absorption analysis confirms the photosensitivity of g-C3N4 upon interaction with toxic molecules. [ABSTRACT FROM AUTHOR]

The therapeutic effects of the plant Hibiscus sabdariffa are attributed significantly to the flavonoid Hibiscetin. Water and ethanol are frequently used as solvents in the extraction of flavonoids. Hydrogen bonding interactions are highly significant in the extraction process. Density functional theory (DFT) methods were used in the present investigation to theoretically examine hydrogen bonding interactions between Hibiscetin and ethanol/water. Molecular geometries, interaction energies, topological and charge studies of the complexes were investigated using the 6–311+G(d,p) basis set at the B3LYP-GD3 and M06–2X levels of theory. Eleven Hibiscetin-CH3CH2OH and nine Hibiscetin-H2O stable complexes were obtained after thorough optimization. 8OH and 5′OH positions were found to be the ideal interaction sites. The hydrogen bonds formed by the hydroxyl hydrogen atoms were moderately strong and partially covalent by the QTAIM, NCI, and ELF analyses. The MEP and NBO analyses validated the electron and charge transport from the hydrogen bond donor to the acceptor.

Lamotrigine is a medication used to treat epilepsy and help stabilize mood in individuals with bipolar disorder. Epilepsy includes different types of seizures, such as focal seizures, tonic-clonic seizures, and Lennox-Gastaut syndrome, and Lamotrigine is specifically designed to manage this condition. The effectiveness of the drug relies on how it interacts with different liquid environments. In our study, we employed two methods, namely PBE0-D3/def2-TZVP, for optimizations and various calculations. We utilized this approach for NBO, NCI, and wavefunction assay. Additionally, we used PBE0-D3/def2-TZVP and DLPNO-CCSD(T) for analyzing LED, MD, and the bond energy of Lamotrigine in both a vacuum and a complex setting (with water and DMSO). Our findings revealed that Lamotrigine can break down into four fragments: triazine, dichlorophenyl-, 10 amine at the second position in triazine, and 10 amines at the fourth position in triazine. The bond energy for these fragments is measured at 351.84 kcal/mol. NBO provided insights into the electronic transition energies of Lamotrigine in different environments, including a vacuum and with solvents. NCI helped us understand the non-covalent interactions of Lamotrigine in both a vacuum and with water and DMSO (complex) molecules through their two pores: inter and intra interactions. We further explored binding energies and total binding energies of Lamotrigine with water and DMSO. Simulations indicated that Lamotrigine with DMSO pore1 exhibited the highest energy changes over time with a positive sign, while Lamotrigine with water pore2 showed the lowest energy changes over time with a negative sign. In our implicit solvation assay using the SMD model and the CPCM method, we found that Lamotrigine with water had a lower free energy compared to the Lamotrigine-DMSO system.

The newly synthesized imidazole derivative namely, 4,5-bis[(E)-2-phenylethenyl]-1H,1′H-2,2′-biimidazole (KA1), was studied for its molecular geometry, docking studies, spectral analysis and density functional theory (DFT) studies. Experimental vibrational frequencies were compared with scaled ones. The reactivity sites were determined using average localized ionization analysis (ALIE), electron localized function (ELF), localized orbital locator (LOL), reduced density gradient (RDG), Fukui functions and frontier molecular orbital (FMO). Due to the solvent effect, a lower gas phase energy gap was observed. Through utilization of the noncovalent interaction (NCI) method, the hydrogen bond interaction, steric effect and Vander Walls interaction were investigated. Molecular docking simulations were employed to determine the specific atom inside the molecules that exhibits a preference for binding with protein. The parameters for the molecular electrostatic potential (MESP) and global reactivity descriptors were also determined. The thermodynamic characteristics were determined through calculations employing the B3LYP/cc-pVDZ basis set. Antimicrobial activity was carried out using the five different microorganisms like Escherichia coli, Streptococcus pneumoniae, Staphylococcus aureus, Klebsiella pneumoniae and Candida albicans.

Textbooks show that in cis-1,3-disubstituted cyclohexane molecule, the conformer with the substituents in the diaxial positions is higher in energy and hence, it presents a low population in the conformational equilibrium. The diaxial conformer is destabilized by the repulsion between the substituent groups and the axial hydrogen atoms on the same side of the ring. This interaction is known as the 1,3-diaxial interaction. In this study, the solvent effect on the conformational equilibria of cis-3-N-ethylaminocyclohexanol (cis-3-EACOL) and cis-3-N,N-diethylaminocyclohexanol (cis-3-DEACOL) has been assessed through the spin-spin coupling constant (3JHH). The results show that the diaxial conformation of cis-3-EACOL decreases from 92% in CCl4 (∆Gee−aa = 1.48 kcal mol−1) to 10% in DMSO-d6 (∆Gee−aa = −1.31 kcal mol−1). For cis-3-DEACOL the diaxial conformer decreased from 36% in CCl4 (∆Gee−aa = −0.33 kcal mol−1) to 7% in Pyridine-d5 (∆Gee−aa = −1.55 kcal mol−1). The stabilization of the diaxial conformer in nonpolar solvents takes place due to the O-H···N intramolecular hydrogen bond, which overcomes the 1,3-diaxial steric interactions.

A novel series of multifunctional pyrazolo[3,4-d]pyrimidine-based glutamate analogs (6a–l and 7a,b) have been designed and synthesized as antifolate anticancer agents. Among the tested compounds, 6i exhibited the most potent anti-proliferative activity towards NSCLC, CNS, Ovarian, Prostate, Colon, Melanoma, Breast, and Renal cancers with good to weak cytostatic activity and non-lethal actions. 6i demonstrated higher selectivity for cancer than normal cells. 6i could significantly increase the accumulation of S-phase cells during the cell cycle distribution of cancer cells with high potency in the induction of apoptosis. The results unveiled that 6i probably acts through dual inhibition of DHFR and TS enzymes (IC50 = 2.41 and 8.88 µM, correspondingly). Docking studies of 6i displayed that N1-p-bromophenyl and C3-Methyl groups participate in substantial hydrophobic interactions. The drug-likeness features inferred that 6i met the acceptance criteria of Pfizer. Taking together, 6i could be a promising prototype for further optimization as an effective anticancer drug. [ABSTRACT FROM AUTHOR]

Fluvoxamine has been proven in studies to improve the immune system by reabsorbing serotonin and to be beneficial in limiting the spread of covid‐19 (in the early stages of the disease). The interaction between pristine fluvoxamine drug and serotonin, as well as the interaction between NO2/NH2 doped fluvoxamine drug and serotonin, was investigated in this work using the quantum theory of atom in the molecule (QTAIM) and density‐functional theory (DFT) at the B3LYP/6‐311+G (d,p) (gas phase and water media) computational level. The NH2 and NO2 doping on fluvoxamine significantly increased the adsorption energy of serotonin and improved the dipole moment, solvent energy, chemical hardness/softness, and charge/energy transfer. On the other hand, according to the results of this study, NH2 doping compared to NO2 had no significant effect on the electronic properties such as HOMO/LUMO orbital energy and its gap. From the results, the binding energy of the most stable structure (Complex‐A) was measured to be 12.59 and 11.65 kcal/mol. Based on the electronic structure analysis, an assessment of the stability of the studied systems in the gas phase reveals the following trend: Fluvoxamine‐NH2>Fluvoxamine‐NO2>Fluvoxamine‐NH2/Ser>Fluvoxamine‐NO2/Ser, with corresponding energy gaps of 4.12, 2.65, 1.98, and 1.63 eV, respectively. Therefore, NH2 doping on fluvoxamine is a harmless electronic interaction and does not significantly change the properties of the drug. It seems that increasing the absorption energy by doping the NH2 functional group can help reduce the therapeutic dose and make fluvoxamine more effective. [ABSTRACT FROM AUTHOR]

The target molecule 2,6-bis(4-hydroxy-3-methoxyphenyl)-3,5-dimethylpiperidin-4-one (BHMD) has best binding energy of –7.5 kcal/mol with 5YOK protein of HIV-1 protease. The theoretical studies of the target molecule have been carried out using Gaussian 16W software and viewed by Gaussview 06 software. Bond length, bond angle and dihedral angle of optimized geometry have been performed by DFT method with B3LYP/6-311G (d,p) basis set. The charge transfer and electronic properties of the target molecule have been explained on the basis of highest occupied molecular orbital and lowest unoccupied molecular orbital and its energy values have been used for calculating the global chemical reactivity parameters. In addition to that, molecular electrostatic potential and Mulliken population analysis have been calculated and discussed for predicting the reactive site. NBO analysis has been used to study the charge delocalization and stability of the molecule. NCI and shaded surface map with projection effect of electron localization function have also been studied by Multiwfn 3.8 software. [ABSTRACT FROM AUTHOR]

In the present study, the title compound is named 4-((5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)(6-methoxynaphthalen-1-yl)methyl)-5-methyl-2-phenyl-1,2-dihydropyrazol-3-one was synthesized, and its antibacterial, antifungal, cytotoxic activity was studied by both experimental and in silico methods. The molecular structure was optimized using DFT/B3LYP method with cc-pVDZ as a besis set, and frontier molecular orbital (FMO) studies was used to explain the physiochemical properties of that molecule by the energy of interacting orbitals. NBO describes the intra delocalization of electrons in the molecule, which support the stability of that molecule. Noncovalent interaction (NCI) explains the nonbond interactions present in the molecule. Drug-likeness property of 405 C have been checked by absorption, distribution, metabolism and excretion (ADME) assay, result shown all the drug-likeness properties in red color region, so we have confirmed this molecule as a drug. 405 C undergoes antibiotic activity against P. aeruginosa organism, antifungal activity against B. cinerea and cytotoxicity activity against MCF-7 and HeLa cell when compared to standard drugs. [ABSTRACT FROM AUTHOR]

A novel series of multifunctional pyrazolo[3,4-d]pyrimidine-based glutamate analogs (6a–l and 7a,b) have been designed and synthesized as antifolate anticancer agents. Among the tested compounds, 6i exhibited the most potent anti-proliferative activity towards NSCLC, CNS, Ovarian, Prostate, Colon, Melanoma, Breast, and Renal cancers with good to weak cytostatic activity and non-lethal actions. 6i demonstrated higher selectivity for cancer than normal cells. 6i could significantly increase the accumulation of S-phase cells during the cell cycle distribution of cancer cells with high potency in the induction of apoptosis. The results unveiled that 6i probably acts through dual inhibition of DHFR and TS enzymes (IC50 = 2.41 and 8.88 µM, correspondingly). Docking studies of 6i displayed that N1-p-bromophenyl and C3-Methyl groups participate in substantial hydrophobic interactions. The drug-likeness features inferred that 6i met the acceptance criteria of Pfizer. Taking together, 6i could be a promising prototype for further optimization as an effective anticancer drug.

Context: Oligothiophenes have long been used as model compounds to understand the chemistry of polythiophenes. Herein, we have some quantum chemical calculations and intra- and inter-molecular interaction calculations of a series of oligothiophenes such as terthiophene, quintetthiophene, sevensthiophene, terthiophene-terthiophene, terthiophene-water, terthiophene-methanol, and terthiophene-chloroform performed by time-dependent density functional theory (TD-DFT), density functional theory (DFT), and Multiwfn: a multifunctional wavefunction analyzer. The UV-vis spectra, HOMO-LUMO energies, NBO analysis, MEP, molecular structures, and electronic properties were computed using DFT/TD-DFT at the level of B3LYP/6-31+ G (d,p) and described. The nature of molecular interactions between terthiophene and solvents like water, methanol, and chloroform were also investigated using non-covalent interaction index (NCI), reduced density gradient (RDG), localized orbital locator (LOL), and electron localization function (ELF) topological analyses. Besides, Fukui functions and energy of population density-of-states were computed using the same method. The calculation results show that there are some changes in the terthiophene with the addition of solvent to the medium. Methods: DFT calculations were performed using the Gaussian 09 software and GaussView 5.0 visulation program. Multiwfn software is used to calculate the reduced density gradient (RDG) scatterplots, non-covalent interactions (NCI), ELF, LOL, Fukui analysis, and energy of population density-of-states of oligothiophenes. [ABSTRACT FROM AUTHOR]

Abstract Introduction Tobacco cessation is a critical but challenging intervention for cancer patients. Our National Cancer Institute‐designated Comprehensive Cancer Center instituted a tobacco cessation program in 2019. This manuscript reports on the first 2 years of our experience. Methods Patients were referred to the program by their care team, and a certified tobacco treatment specialist contacted patients remotely and provided behavioral therapy and coordinated pharmacotherapy. We retrospectively captured data from patients with a cancer diagnosis referred to the tobacco cessation program. Univariate and multivariable logistic regression analyses with the backward elimination approach were performed to determine factors associated with patient acceptance of referral to the tobacco cessation program. Tobacco cessation rates after referral to the program were also captured. Results Between July 2019 and August 2021, 194 patients were referred to the tobacco cessation program. Of the 194 patients referred, 93 agreed to enroll in the tobacco cessation program (47.9%), of which 84 requested pharmacotherapy (90.3%). Twenty‐four were able to cease tobacco use (25.8%). Only 7 patients out of the 101 patients (6.9%) who declined cessation services were successful (p

Yosef Zenebe,1 Baye Akele,2 Mulugeta W/Selassie,3 Mogesie Necho1 1Department of Psychiatry, Wollo University, Dessie, Ethiopia; 2Department of Pharmacy, Wollo University, Dessie, Ethiopia; 3Department of Pediatrics and Child Health Nursing, Wollo University, Dessie, EthiopiaCorrespondence: Yosef Zenebe, Email yosef.zenebe79@gmail.com; yosef.zenebe@wu.edu.etBackground: Neurocognitive impairment (NCI) is one of the most common neurological complications in HIV-positive individuals, particularly in resource-limited countries. Neurocognitive impairments can occur at any stage of HIV infection, although the risk increases as the infection progresses. However, in Africa, there are few studies with highly variable and inconsistent results. Therefore, this study aimed to determine the prevalence and factors associated with NCI among HIV-positive people in Africa.Methods: For this systematic review and meta-analysis, we used PubMed/Medline, Scopus, Web of Science, the Cochrane Library, Embase, and PsycINFO to comprehensively search a number of papers. Studies reporting the prevalence of NCI and its factors were included in the estimation of the pooled prevalence. A consistent data extraction format was created in Microsoft Excel to extract the data, which was then imported into STATA 11 statistical software for analysis. The heterogeneity was evaluated using the I2 test, and a random effect meta-analysis model was employed to calculate the pooled prevalence of NCI because the included studies showed significant heterogeneity.Results: In all, Africa had a pooled prevalence of NCI of 45.15% (95% CI: 36.86, 53.43). According to the subgroup analysis of this study, West Africa had the lowest frequency, at 42.40% (95% CI: 22.03, 62.77), whereas Central and South Africa had the highest prevalence, at 49.33% (95% CI: 10.72– 87.95).Conclusion: In Africa, the cumulative prevalence of NCI was high. Being a woman, not having a formal education, those with only an elementary education, being older, having late-stage HIV, and abusing drugs were all often associated with NCI. The average burden of NCI in Africa is high and that would be a significant figure for interventional actions in the area.Keywords: Africa, meta-analysis, NCI, HIV

Two new coordination compounds comprising Mn(II) and Cu(II) viz. [Mn(bz)2(Hdmpz)2(H2O)] (1) and [Cu(crot)2(Hdmpz)2] (2) (where, bz = benzoate; crot = crotonate; Hdmpz = 3, 5-dimethyl pyrazole) were synthesized and characterized. The characterization involved a single crystal X-ray diffraction technique, FT-IR spectroscopy, electronic spectroscopy, TGA, and elemental analyses. Compounds 1 and 2 crystallize as mononuclear entities of Hdmpz with penta-coordinated Mn(II) and hexa-coordinated Cu(II), respectively. These complexes exhibit distorted trigonal bipyramidal and distorted octahedral geometries, respectively. A crystal structure analysis of compound 1 elucidates the existence of C–H⋯π and π-stacking interactions alongside O–H⋯O, N–H⋯O, and C–H⋯O H-bonding interactions contributing to the stabilization of the compound’s layered assembly. Similarly, in compound 2, the crystal structure stability is attributed to the presence of hydrogen bonding in conjugation with π-stacking interactions. We conducted theoretical investigations to analyze π⋯π, H-bonding, and antiparallel CH···π non-covalent interactions observed in compounds 1 and 2. DFT calculations were performed to find out the strength of these interactions energetically. Moreover, QTAIM and non-covalent interaction (NCI) plot index theoretical tools were employed to characterize them and evaluate the contribution of the H-bonds.

A new class of benzimidazole-based derivatives (4a–j, 5, and 6) with potential dual inhibition of EGFR and BRAFV600E has been developed. The newly synthesized compounds were submitted for testing for antiproliferative activity against the NCI-60 cell line. All newly synthesized compounds 4a–j, 5, and 6 were selected for testing against a panel of sixty cancer cell lines at a single concentration of 10 µM. Some compounds tested demonstrated remarkable antiproliferative activity against the cell lines tested. Compounds 4c, 4e, and 4g were chosen for five-dose testing against 60 human tumor cell lines. Compound 4c demonstrated strong selectivity against the leukemia subpanel, with a selectivity ratio of 5.96 at the GI50 level. The most effective in vitro anti-cancer assay derivatives (4c, 4d, 4e, 4g, and 4h) were tested for EGFR and BRAFV600E inhibition as potential targets for antiproliferative action. The results revealed that compounds 4c and 4e have significant antiproliferative activity as dual EGFR/BRAFV600E inhibitors. Compounds 4c and 4e induced apoptosis by increasing caspase-3, caspase-8, and Bax levels while decreasing the anti-apoptotic Bcl2 protein. Moreover, molecular docking studies confirmed the potential of compounds 4c and 4e to act as dual EGFR/BRAFV600E inhibitors.

Following our previous surveys on group 14 divalents, we report new series of N‐heterocyclic germylenes (NHGe) and their analogs that are regarded as cyclic (1C–10C) and linear (1L–10L) forms. Their thermodynamic and structural parameters are compared and contrasted, at the B3LYP/6‐311++G** level of theory. The complexation of these NHGe with Cu metal is investigated. Various analyses such as the atoms in molecules (AIM), natural bond orbital (NBO), non‐covalent interaction (NCI), and ultraviolet‐visible (UV‐Vis) are performed to determine the strength of our germylenes to act as ligands. The results indicate that there are strong interactions between the metal‐ligand bonds with a high contribution of π‐back donation. Every linear germylene demonstrates a higher ability of σ‐donation and π‐acceptation. Our scrutinized germylenes turn out as remarkable ligands to the Cu that can be applied in several types of catalysis. [ABSTRACT FROM AUTHOR]

The proposed study concerns the inclusion complexation of dimethoate (DMT) in the β-cyclodextrin (β-CD) molecule cage using a 1:1 stoichiometry. The interactions between DMT and β-CD were evaluated using PM7 and DFT in water and gas, using the CAMB3LYP functional 6-31G(d,p) basis set. All approaches agree with the optimal 3D structure, which includes full DMT inclusion in the β-CD cavity. Complexation, LUMO, and HOMO energies were computed. The natural bond orbital (NBO) and UV–visible calculations were determined and discussed. Additionally, the non-covalent intermolecular interactions between dimethoate and β-cyclodextrin are investigated through RDG, NCI, and IGM. The main forces stabilizing the examined inclusion complex are H-bond and van Der Waals interactions. Furthermore, the energy decomposition analysis (EDA) was applied highlighting the H-bonding by quantifying its strength. The TD-DFT method provided the electronic UV–vis spectra showing significant electronic transitions between the host and the guest by observing the molecular orbitals localizations. [ABSTRACT FROM AUTHOR]

Two Na(I) coordination polymers, namely, {Na(BA)2(μ-H2O)2}n{adp}n (1) and {[Na2(μ-BA)(μ-fum)(μ-H2O)4](BA)}n (2) (where, BA = boric acid, adp = adipic acid, fum = fumarate),were prepared and characterized using elemental analysis, TGA, FT-IR, and single-crystal X-ray diffraction techniques. Various unconventional supramolecular interactions, i.e., CH∙∙∙HC and parallel CO∙∙∙CO interactions, stabilize the layered assembly of compound 1. Interesting dual enclathration of BA molecules within the supramolecular host cavities formed by O-H∙∙∙O and C-H∙∙∙C interactions stabilizes the crystal structure of compound 2. The H-bonding interactions in 1 and 2 were further studied theoretically using the quantum theory of atoms in molecules (QTAIM) and the noncovalent interaction plot (NCI Plot) computational tools. The energy of the H-bonds was estimated using the potential energy density at the bond critical points. Theoretical calculations confirmed the presence of O-H∙∙∙O H-bonding interactions in both compounds, forming structure-guiding R 2 2 (8) synthons relevant for the stability of the compounds. [ABSTRACT FROM AUTHOR]

The set of TX3-TrX2 (T = C, Si, Ge; Tr = B, Al, Ga; X = F, Cl, Br) molecules offers a rather unique opportunity to study both σ-hole and π-hole dimerization on the tetrel and triel ends, respectively. According to the molecular electrostatic potential (MEP) distribution, the π-hole extrema (acidic sites) were more intense than their σ-hole counterparts. The molecules owning the most (CX3-AlX2) and least (SiX3-BX2) intense π-holes were chosen to evaluate their capacities to attract one and two HCN molecules (Lewis bases). We discovered that the energetic characteristics of π-hole dimers severely conflict with the monomers MEP pattern since the weakest π-hole monomer forms a dimer characterized by interaction energy compared to those created by the monomers with noticeably greater power in the π-hole region. This outcome is due to the deformation of the weakest π-hole donor. Furthermore, the MEP analysis for monomers in the geometry of respective dimers revealed a "residual π-hole" site that was able to drive second ligand attachment, giving rise to the two "unusual trimers" examined further by the NCI and QTAIM analyses. Apart from them, the π-hole/π-hole and σ-hole/π-hole trimers have also been obtained throughout this study and described using energetic and geometric parameters. The SAPT approach revealed details of the bonding in one of the "unusual trimers". Finally, Born-Oppenheimer Molecular Dynamics (BOMD) simulations were carried out to investigate the time evolution of the interatomic distances of the studied complexes as well as their stability. [ABSTRACT FROM AUTHOR]

The urea under high pressure is analyzed from a theoretical point of view using the quantum theory of atoms in molecules and the non-covalent interactions index. For this purpose, four urea crystal structures from X-ray, obtained for different pressures, were used to obtain their electronic structure with the relaxation of hydrogen atom positions using the density functional theory with periodic boundary conditions. From our analysis, the quantum chemistry predictors found N–H ⋯ O hydrogen bonds reported experimentally. Additionally, we found N–H ⋯ N hydrogen bonds, which have not been mentioned or underestimated by experimental arguments. We show that the N–H ⋯ N hydrogen bonds are essential in the description of the urea under high pressure. Furthermore, weak non-covalent interactions, not just hydrogen bonds, become crucial in stabilizing experimental structures under high pressure. This article presents a theoretical description of the molecular interactions involved in urea under high pressure for the first time. [ABSTRACT FROM AUTHOR]

Claisen and Cope rearrangements are [3,3]-sigmatropic rearrangements thermally activated that occur through six-membered transition states. Although extensively investigated for decades, little is known about the magnetochemistry of these rearrangements. In view of this, we carried out an investigation based on chemical-computational models through methods based on Density Functional Theory, QTAIM, Multicenter Bond Order, NCI, GIAO, and GIMIC. We demonstrated that CCR mechanisms are concerted in which the 6-membered cyclic transition states present high aromaticity character. The molar and anisotropic susceptibility, NICS(1), and NICSzz signals were verified to have a good correlation with J (nA T−1). However, these indices demonstrated insufficient to evaluate the magnitudes of aromaticity in these transition states. Among the magnetic and topological descriptors applied in this work, the magnetically induced current density (J) proved, this to be an excellent strategy for theoretically estimative of the aromaticity of the transition states involved in the investigated rearrangements. Among the rearrangements with chair conformation, it was noted that the higher aromaticity is associated with the less favoured kinetics. For chair conformations, Claisen rearrangement (TS2) presents J = 8.63 nA T−1 and Cope (TS4) presents J = 10.43 nA T−1. However, the following order of aromaticity TS4 > TS2 > TS3 > TS1, with high paramagnetic currents in the boat conformations reducing the total current in the ring, suggests that it is not possible to establish a direct correlation between aromaticity and the kinetics of the Cope and Claisen rearrangements, since the most stable transition estate geometries are not necessarily the most aromatic. [ABSTRACT FROM AUTHOR]

BackgroundFew adolescents and young adults (AYAs, 15-39 years old) enroll onto cancer clinical trials, which hinders research otherwise having the potential to improve outcomes in this unique population. Prior studies have reported that AYAs are more likely to receive cancer care in community settings. The National Cancer Institute (NCI) has led efforts to increase trial enrollment through its network of NCI-designated cancer centers (NCICC) combined with community outreach through its Community Clinical Oncology Program (CCOP; replaced by the NCI Community Oncology Research Program in 2014).MethodsUsing AYA proportional enrollment (the proportion of total enrollments who were AYAs) as the primary outcome, we examined enrollment of AYAs onto SWOG therapeutic trials at NCICC, CCOP, and non-NCICC/non-CCOP sites from 2004 to 2013 by type of site, study period (2004-08 vs 2009-13), and patient demographics.ResultsOverall, AYA proportional enrollment was 10.1%. AYA proportional enrollment decreased between 2004-2008 and 2009-2013 (13.1% vs 8.5%, P

Amphotericin B (AmB) is an antibiotic with a wide spectrum of action and low multidrug resistance, although it exhibits self-aggregation, low specificity, and solubility in aqueous media. An alternative for its oral administration is its encapsulation in polymers modified with bioconjugates. The aim of the present computational research is to determine the affinity between AmB and six bioconjugates to define which one could be more suitable. The CAM-B3LYP-D3/6-31+G(d,p) method was used for all computational calculations. The dimerization enthalpy of the most stable and abundant systems at pH = 7 allows obtaining this affinity order: AmB_1,2-distearoyl-sn-glycerol-3-phosphorylethanolamine (DSPE) > AmB_γ-cyclodextrin > AmB_DSPEc > AmB_retinol > AmB_cholesterol > AmB_dodecanol, where DSPEc is a DSPE analog. Quantum theory of atoms in molecules, the non-covalent interactions index, and natural bond orbital analysis revealed the highest abundance of noncovalent interactions for AmB-DSPE (51), about twice the number of interactions of the other dimers. Depending on the interactions' strength and abundance of the AmB-DSPE dimer, these are classified as strong: O-H---O (2), N-H---O (3) and weak: C-H---O (25), H---H (18), C-H---C (3). Although the C-H---O hydrogen bond is weak, the number of interactions involved in all dimers cannot be underestimated. Thus, non-covalent interactions drive the stabilization of copolymers, and from our analysis, the most promising candidates for encapsulating are DSPE and γ-cyclodextrin. [ABSTRACT FROM AUTHOR]

Introduction: Tobacco cessation is a critical but challenging intervention for cancer patients. Our National Cancer Institute‐designated Comprehensive Cancer Center instituted a tobacco cessation program in 2019. This manuscript reports on the first 2 years of our experience. Methods: Patients were referred to the program by their care team, and a certified tobacco treatment specialist contacted patients remotely and provided behavioral therapy and coordinated pharmacotherapy. We retrospectively captured data from patients with a cancer diagnosis referred to the tobacco cessation program. Univariate and multivariable logistic regression analyses with the backward elimination approach were performed to determine factors associated with patient acceptance of referral to the tobacco cessation program. Tobacco cessation rates after referral to the program were also captured. Results: Between July 2019 and August 2021, 194 patients were referred to the tobacco cessation program. Of the 194 patients referred, 93 agreed to enroll in the tobacco cessation program (47.9%), of which 84 requested pharmacotherapy (90.3%). Twenty‐four were able to cease tobacco use (25.8%). Only 7 patients out of the 101 patients (6.9%) who declined cessation services were successful (p < 0.001). On univariate logistic regression, race (p = 0.027) and marital status (p = 0.020) were associated with referral acceptance. On multivariable analysis, single patients (odds ratio [OR] = 0.33) and Caucasian patients (OR = 0.43) were less likely to accept a referral. Conclusions: Access to tobacco cessation services is a critical component of comprehensive cancer care. Our experience highlights the need to understand patient‐specific factors associated with engagement with a tobacco cessation program during cancer treatment. The use of pharmacotherapy is also a critical component of successful tobacco cessation. [ABSTRACT FROM AUTHOR]

3,4,5‐trihydroxybenzlic acid (gallic acid) and its derivatives exist mostly as secondary metabolites of the phenol family found in plants. Herein, the interaction of gallic acid (GA), methylgallic acid (MGA), ethylgallic acid (EGA) with cytosine (the most reactive part of DNA) has been studied in detail using first principle density functional theory (DFT). Several interaction configurations between the gallic acid and selected derivatives have been investigated using DFT at the M06‐2X/6‐31+G(d,p) theoretical method, topological analysis based on quantum theory of atoms‐in‐molecule (QTAIM), and the noncovalent interaction (NCI) which aid in the understanding of interactions between studied compounds. The results obtained from the interaction energy and energy decomposition analysis (EDA) show that methylgallate (GA) has the largest interaction energy with cytosine, along with the strongest H‐bond interaction and is best suited for drug design due to its lowest value of stabilization energy at the interaction site 1.Similarly, weak interactions were observed between EGA and cytosine of DNA between −0.02 to 0.01 a.u with a sparing trace of H bond with the aid of non‐covalent interaction (NCI). The reactivity of the studied compound depicts GA to be the most reactive. Although gallic acid competes favorably, this study, however, revealed the great potential of its derivatives: EGA and MGA having great potential for drug design. Their applications are vast and mostly hinged on antioxidant properties, especially in the pharmaceutical industry and, hence, form the basis of an effective class of phytomedicines. [ABSTRACT FROM AUTHOR]

Background: Clinical trial diversity is critical to advance health and health equity. Research addressing the discrepancy between goals of achieving clinical trial diversity and realities of study enrollment remains underdeveloped. Objective: This study aims to examine the association between race/ethnicity and clinical trial invitation, participation, knowledge, and sources of influence on clinical trial participation. Design and Participants: A cross-sectional, observational study using nationally representative data from 3689 US adults (≥ 18 years of age) who responded to the Health Information National Trends Survey fielded from February 24 to June 15, 2020. Main Measures: Primary outcomes included clinical trial invitation, participation, knowledge, and sources of influence on participation. The independent variable of interest is self-reported race/ethnicity. Key Results: Respondents identifying as non-Hispanic Black (relative to non-Hispanic White) had higher odds of being invited into a clinical trial (adjusted odds ratio: 2.0, 95% confidence interval (CI): 1.1, 3.7), but no differences in odds of participation were observed by race/ethnicity. Respondents from all races/ethnicities reported that personal healthcare providers were the most trusted source of clinical trial information. Hispanic (marginal effect (ME): − 0.09; 95% CI: − 0.16, − 0.03), non-Hispanic Black (ME: − 0.11; 95% CI: − 0.18, − 0.04), and non-Hispanic other (ME: − 0.11; 95% CI: − 0.19, − 0.02) respondents had lower odds than non-Hispanic White respondents of saying they would be influenced "a lot" by their doctor encouraging participation. Non-Hispanic Black respondents had significantly lower odds (relative to non-Hispanic White) of indicating family encouragement would influence their clinical trial participation decision "a lot" (ME: − 0.09; 95%: CI: − 0.14, − 0.03). Conclusion: While personal healthcare providers were trusted sources of information, racial/ethnic minority populations noted lower odds of clinical trial participation influence from providers and family. Thus, it is imperative for the healthcare, government, and industry organizations to build trust in medicine and science. [ABSTRACT FROM AUTHOR]

The encapsulation of a set of small molecules, H2, CO, CO2, SO2, and SO3, by a circular C18 ring is investigated by quantum calculations. These ligands lie near the center of the ring but, with the exception of H2, are disposed roughly perpendicular to the ring plane. Their binding energies with the C18 vary from 1.5 kcal/mol for H2 up to 5.7 kcal/mol for SO2, and the bonding is dominated by dispersive interactions spread over the entire ring. The binding of these ligands on the outside of the ring is weaker but allows the opportunity for each to bond covalently with the ring. A pair of C18 units lie parallel to one another. This pair can bind each of these ligands in the area between them with only small perturbations of the double ring geometry. The binding energies of these ligands to this double ring configuration are amplified by some 50% compared to the single ring systems. The presented data concerning the trapping of small molecules may have larger implications regarding hydrogen storage or air pollution reduction. [ABSTRACT FROM AUTHOR]

The present work focuses on the structural and antioxidant ability of the naturally occurring flavonol Hibiscetin and its glycoside Hibiscitrin investigated in gas, water, and benzene media using M06-2X functional level of density functional theory with 6–311 + G (d, p) basis set. Relaxed potential energy scans of the hydroxyl groups and the quantum theory of atoms in molecules are used to study the strength of intramolecular hydrogen bonding and non-covalent interactions, which are critical for the antioxidant action of polyphenols. Thermodynamic factors associated with polyphenols' three primary anti-radical mechanisms have been investigated. Both molecules were found to exhibit the same trend in their reaction enthalpies. The bond dissociation enthalpies of Hibiscetin are lower than Hibiscitrin. However, the difference is not well pronounced. Their comparable reactivity is confirmed by the examination of Frontier molecular orbitals (FMO) and global descriptive characteristics. According to the study, radical attacks prefer to occur at the 8-OH position. The FMO and electrostatic potential map confirm the location of the active site. [ABSTRACT FROM AUTHOR]

This study focuses on selected members of the general salen-analogues family possessing two O-H⋯N hydrogen bonds, namely three isomers of N,N'-bis(salicylidene)-X-phenylenediamine, denoted as ortho, meta and para. Two of the isomers are not planar in the published crystal structures. The current study tackles the problem of symmetry and interactions within the molecules, as well as in the crystal lattice. The aromaticity of the phenyl rings is evaluated using the Harmonic Oscillator Model of Aromaticity (HOMA) index. Intra- and inter-molecular non-covalent interactions are studied via Hirshfeld surface analysis, Independent Gradient Model (IGM), Quantum Theory of Atoms in Molecules (QTAIM), Non-Covalent Interaction (NCI) index, Electron Localisation Function (ELF), Core-Valence Bifurcation (CVB) index and Symmetry-Adapted Perturbation Theory (SAPT). Density Functional Theory (DFT) simulations were carried out in vacuo and with solvent reaction field based on Polarisable Continuum Model (IEF-PCM formulation) at the ω B97XD/6-311+G(2d,2p) level. Crystal structure analyses were performed for the data reported previously in the literature. The obtained results demonstrate that the three isomers differ greatly in their structural properties (molecular symmetry is broken for the ortho and meta isomers in the solid state) and ability to form intermolecular interactions, while retaining overall similar physico-chemical characteristics, e.g., aromaticity of the phenyl rings. It was found that the presence of the polar solvent does not significantly affect the structure of the studied compounds. An application of the Hirshfeld surface analysis revealed the nature of the non-covalent interactions present in the investigated crystals. The SAPT results showed that the stability of the dimers extracted from the crystals of the Schiff base derivatives arises from electrostatics and dispersion. [ABSTRACT FROM AUTHOR]

In the present study, a couple of simple models were presented to estimate the energy of individual hydrogen bonds in traditional base pairs. In this regard, formamide and formamidine dimers and a set of their derivatives with different functional groups such as F, Cl, Br, CH3, CN, ethynyl, nitroso, and vinyl were considered. All of these structures are optimized by M06-2X and MP2 methods in conjunctions with 6–311 + + G(d,p) basis set. The computational results showed that the hydrogen bond energy in the first method is higher than the MP2 and also the NHN interactions are stronger than the corresponding NHO ones. Moreover, the relationships between the energy hydrogen bonds and all of the geometrical, topological, and molecular orbital descriptors were also explored. The absolute values of the correlation coefficient (R2) indicated the best linear relationships between the electron density at the hydrogen bond critical point (ρ(r)) and the energy of NHN (R2 = 0.98) and NHO (R2 = 0.82) hydrogen bonds. Based on these equations, it was found that the orders of calculated individual HB energies of the Watson–Crick base pairs are completely similar to the compliance constant model of Gruenberg. Finally, the energy of individual bonds in a set of usual base pairs was evaluated and compared with their complexation energies. The slight difference between ƩEHB and ΔEComp reflects the high accuracy of the proposed models and equations. [ABSTRACT FROM AUTHOR]

Two Ni(II) complexes with the formula [{Ni(dppf)}2{(L1)2}](PF6)2 (Ni-I) and [{Ni(dppe)}2{(L1)2}](PF6)2 (Ni-II) were prepared by reacting [Ni(dppf)Cl2] and [Ni(dppe)Cl2] (dppf = 1,1′-Bis-(diphenylphosphino)ferrocene; dppe = 1,2-Bis-(diphenylphosphino)ethane) with secondary amine piperazine derived ligand disodium bis-(dithiocarbamate)piperazine ((piper(dtc)2 = L1) and counter anion PF6−. These complexes were characterized by elemental analyses, FT-IR, 1H, 13C and 31P NMR, UV-Vis. spectroscopy and single crystal X-ray diffraction. The X-ray analyses reveal centrosymmetric structures where each Ni(II) centre adopts distorted square planar geometry defined by two sulfur centres of dithiocarbamate ligand and two phosphorus centres of dppf and dppe ligands in Ni-I and Ni-II, respectively. The supramolecular framework of both Ni-I and Ni-II are sustained by C-H⋯π and C-H⋯F interactions, and they also display interesting intramolecular C-H⋯Ni anagostic interactions. Further, the nature of these interactions are studied using Hirshfeld surface analyses, DFT and quantum theory of atoms in molecules (QTAIM) calculations. Additionally, non-covalent interaction (NCI) plot analyses were conducted to gain additional insight into these non-covalent interactions. This work is vital in a new approach towards the rational designing of the centrosymmetric molecules with interesting architectures. [ABSTRACT FROM AUTHOR]

A new coordination compound of copper(II) with a tolfenamate ligand of the paddle-wheel-like structure [CuII2(Tolf)4(MeOH)2]∙2MeOH was obtained and structurally characterized. Chemical bonds of Cu(II)∙∙∙Cu(II) and Cu(II)–O were theoretically analyzed and compared with the results for selected similar structures from the CSD database. QTAIM analysis showed that the Cu(II)∙∙∙Cu(II) interaction has a strength comparable to a hydrogen bond, as indicated by the electron density at a critical point. The remaining QTAIM parameters indicate stability of the Cu(II)∙∙∙Cu(II) interaction. Other methods, such as NCI and NBO, also indicate a significant strength of this interaction. Thus, the Cu(II)∙∙∙Cu(II) interaction can be treated as one of the noncovalent interactions that affects the structure of the coordination compound, the packing of molecules in the crystal, and the general properties of the compound. [ABSTRACT FROM AUTHOR]

Using the methods of IR-spectroscopy and quantum chemical calculations, we determined the formation of an H-bond between the 1,2,3-benzotriazole molecule and the molecules of acetone, dioxane, DMF, and DMSO. Quantum chemistry methods have been used to calculate the sums of charge changes in the atoms of the 1,2,3-benzotriazole molecule and of proton acceptor molecules (acetone, dioxane, DMF, and DMSO) due to the formation of their complexes with an H-bond (H-complexes NH…O). The sum of charge changes was taken as a contribution of a covalent component to H-bond formation. It has been established that as the sum of charge changes in N, H, and O or H and O, forming the H-complex, increases, the enthalpy of H-complex formation (EF) decreases. On the contrary, the EO of H-complexes increases when the product of the initial charges on the H and O atoms increases. In the absence of H-complexes, the product of charges was considered the electrostatic component of H-bond formation. The criterion of the value of H-bond EF was the value of a low-frequency shift of the initial position of the maximum IR absorption band of the NH vibration of the 1,2,3-benzotriazole molecule relative to its position in a neutral CCl4 solvent. The results of QTAIM, NCI, and RDG analyses showed that the values of energy densities in BCPs have a positive value in the complexes formed by 1,2,3-benzotriazole with acetone, dioxane, and DMFA, and such hydrogen bonds are electrostatic in nature. In the complex formed by 1,2,3-benzotriazole and DMSO, it has a negative value and a covalent character. The data obtained have allowed for two main conclusions: (i) In the formation of the H-complexes of the 1,2,3-benzotriazole molecule with proton-acceptor molecules containing oxygen atoms, the main contribution to H-bond formation is made by the electrostatic component. (ii) The contribution of the covalent component increases with increasing enthalpy of H-bond formation.

Neutral (n) and zwitterionic (z) forms of cysteine monomers are combined in this work to extensively explore the potential energy surfaces for the formation of cysteine dimers in aqueous environments represented by a continuum. A simulated annealing search followed by optimization and characterization of the candidate structures afforded a total of 746 structurally different dimers held together via 80 different types of intermolecular contacts in 2894 individual non-covalent interactions as concluded from Natural Bond Orbitals (NBO), Quantum Theory of Atoms in Molecules (QTAIM) and Non-Covalent Interactions (NCI) analyses. This large pool of interaction possibilities includes the traditional primary hydrogen bonds and salt bridges which actually dictate the structures of the dimers, as well as the less common secondary hydrogen bonds, exotic X⋯Y (X = C, N, O, S) contacts, and H⋯H dihydrogen bonds. These interactions are not homogeneous but have rather complex distributions of strengths, interfragment distances and overall stabilities. Judging by their Gibbs bonding energies, most of the structures located here are suitable for experimental detection at room conditions. [ABSTRACT FROM AUTHOR]

Thermodynamic and electronic features of new derivatives of 3‐X‐4‐hydroxy‐2(1H)‐quinolone (X = H, OH, OMe, NH2, NMe2, Me, NHMe, F, Cl, CN, CF3, NO2, CCl3, and COH; 1–14) are investigated, at the B3LYP/6‐311++G** level of theory. Structures with electron‐donating groups (EDGs) show higher values of nucleophilicity (N) than those of electron‐withdrawing groups (EWGs), which are proved via Fukui functions. To determine the sensing ability of 1–14, fluoride (F) as an important industrial, chemical, and biological anion is complexed to the 1–14. All 1–14 establish the strong hydrogen bonding with F, which is verified by various analyses including natural bond orbital (NBO), atoms in molecules (AIM), atomic dipole moment corrected Hirshfeld charges (ADCH), and non‐covalent interaction (NCI). The excitation state study provides the noteworthy results of the charge transfer (CT), natural transition orbital (NTO), and the UV‐Vis spectrum. The obtained outcomes promise new series of quinoline‐based chemosensors (QBCs) to detect F. [ABSTRACT FROM AUTHOR]

The naturally occurring sodium alginate (SA) biopolymer from the Sargassum muticum (Yendo) Fensholt was employed as a green organocatalyst for the synthesis of 4H-pyran derivatives. The naturally extracted macromolecule was fully characterized using different analyses, including nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Energy Dispersive X-ray Analysis (EDX). The catalytic activity of SA was investigated in the one-pot reaction between aldehydes, malononitrile, and 1,3-dicarbonyl compounds in water at room temperature, and the corresponding 2-amino-3-cyano-4H-pyran derivatives were obtained with good to excellent yields. This organocatalyst was easily separated from the reaction mixture and reused for at least two consecutive cycles without a significant loss of its catalytic activity or selectivity. From the mechanistic point of view, density functional theory (DFT) and NCI analyses were performed for the first time to explain the regioselectivity outcomes for the synthesis of 2-amino-3-cyano-4H-pyran derivatives using SA as a green organocatalyst. [ABSTRACT FROM AUTHOR]

The co-crystallization of the lead(II) complex [Pb(S2CNEt2)2] with tetraiodoethylene (C2I4) gave the co-crystal, [Pb(S2CNEt2)2]∙½C2I4, whose X-ray structure exhibits only a small change of the crystal parameters than those in the parent [Pb(S2CNEt2)2]. The supramolecular organization of the co-crystal is largely determined by an interplay between Pb⋯S tetrel bonding (TeB) and I⋯S halogen bonding (HaB) with comparable contributions from these non-covalent contacts; the TeBs observed in the parent complex, [Pb(S2CNEt2)2], remain unchanged in the co-crystal. An analysis of the theoretical calculation data, performed for the crystal and cluster models of [Pb(S2CNEt2)2]∙½C2I4, revealed the non-covalent nature of the Pb⋯S TeB (−5.41 and −7.78 kcal/mol) and I⋯S HaB (−7.26 and −11.37 kcal/mol) interactions and indicate that in the co-crystal these non-covalent forces are similar in energy. [ABSTRACT FROM AUTHOR]