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1.
Molecules ; 25(24)2020 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-33339423

RESUMO

The exo⇔endo isomerization of 2,5-dimethoxybenzaldehyde was theoretically studied by density functional theory (DFT) to examine its favored conformers via sp2-sp2 single rotation. Both isomers were docked against 1BNA DNA to elucidate their binding ability, and the DFT-computed structural parameters results were matched with the X-ray diffraction (XRD) crystallographic parameters. XRD analysis showed that the exo-isomer was structurally favored and was also considered as the kinetically preferred isomer, while several hydrogen-bonding interactions detected in the crystal lattice by XRD were in good agreement with the Hirshfeld surface analysis calculations. The molecular electrostatic potential, Mulliken and natural population analysis charges, frontier molecular orbitals (HOMO/LUMO), and global reactivity descriptors quantum parameters were also determined at the B3LYP/6-311G(d,p) level of theory. The computed electronic calculations, i.e., TD-SCF/DFT, B3LYP-IR, NMR-DB, and GIAO-NMR, were compared to the experimental UV-Vis., optical energy gap, FTIR, and 1H-NMR, respectively. The thermal behavior of 2,5-dimethoxybenzaldehyde was also evaluated in an open atmosphere by a thermogravimetric-derivative thermogravimetric analysis, indicating its stability up to 95 °C.

2.
J Mol Model ; 26(12): 341, 2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-33200284

RESUMO

HER-2 type breast cancer is one of the most aggressive malignancies found in women. Tucatinib is recently developed and approved as a potential medicine to fight this disease. In this manuscript, we present the gross structural features of this compound and its reactivity and wave function properties using computational simulations. Density functional theory was used to optimise the ground state geometry of the molecule and molecular docking was used to predict biological activity. As the electrons interact with electromagnetic radiations, electronic excitations between different energy levels are analysed in detail using time-dependent density functional theory. Various intermolecular and intermolecular interactions are analysed and reaction sites for attacking electrophiles and nucleophiles identified. Information entropy calculations show that the compound is inherently stable. Docking with COVID-19 proteins show docking score of - 9.42, - 8.93, - 8.45 and - 8.32 kcal/mol respectively indicating high interaction between the drug and proteins. Hence, this is an ideal candidate to study repurposing of existing drugs to combat the pandemic.


Assuntos
Antineoplásicos/química , Antivirais/química , Betacoronavirus/química , Elétrons , Oxazóis/química , Inibidores de Proteases/química , Piridinas/química , Quinazolinas/química , Proteínas não Estruturais Virais/antagonistas & inibidores , Antineoplásicos/metabolismo , Antivirais/metabolismo , Betacoronavirus/enzimologia , Sítios de Ligação , Cisteína Endopeptidases/química , Cisteína Endopeptidases/metabolismo , Reposicionamento de Medicamentos , Humanos , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Oxazóis/metabolismo , Inibidores de Proteases/metabolismo , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Estrutura Secundária de Proteína , Piridinas/metabolismo , Teoria Quântica , Quinazolinas/metabolismo , Termodinâmica , Proteínas não Estruturais Virais/química , Proteínas não Estruturais Virais/metabolismo
3.
Sci Rep ; 10(1): 20229, 2020 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-33214687

RESUMO

Herein, a facile green synthesis route was reported for the synthesis of Ag-ZnO nanocomposites using potato residue by simple and cost effective combustion route and investigated the photocatalytic degradation of methylene blue (MB) dye. In the preparation potato extract functioned as a biogenic reducing as well as stabilizing agent for the reduction of Ag + , thus eliminating the need for conventional reducing/stabilizing agents. Ag-ZnO nanocomposites with different Ag mass fractions ranging from 2 to 10% were characterized by using XRD, FT-IR, XPS, SEM, TEM, and UV-Vis spectroscopy. XRD analysis revealed that the as prepared Ag-ZnO nanocomposites possessed high crystallinity with hexagonal wurtzite structure. TEM and SEM images showed that the Ag-ZnO nanocomposites in size ranging from 15 to 25 nm have been obtained, and the particle size was found to increase with the increase in percentage of Ag. FTIR results confirmed the characteristics band of ZnO along with the Ag bands. XPS analysis revealed a pair of doublet with peaks corresponding to Ag and a singlet with peaks corresponding to ZnO. With the increase of concentration of Ag in ZnO, the intensity of NBE emission in the PL spectra was observed to be decrease, resulted to the high photocatalytic activity. Photocatalytic properties of Ag-ZnO nanocomposites evaluated against the MB dye under visible-light irradiation showed superior photodegradation of ~ 96% within 80 min for 2% Ag-ZnO nanocomposites. The apparent reaction rate constant for 2% Ag-ZnO nanocomposites was higher than that of other nanocomposites, which proved to be the best photocatalyst for the maximum degradation of MB. Furthermore, various functional parameters such as dosing, reaction medium, concentration variation were performed on it for better understanding. The enhancement in photocatalytic degradation might be due to the presence of Ag nanoparticles on the surface of ZnO by minimizing the recombination of photo induced charge carriers in the nanocomposites.

4.
Int J Mol Sci ; 21(22)2020 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-33233673

RESUMO

A new double-open-cubane core Cd(II)-O-Cu(II) bimetallic ligand mixed cluster of type [Cl2Cu4Cd2(NNO)6(NN)2(NO3)2].CH3CN was made available in EtOH/CH3CN solution. The 1-hydroxymethyl-3,5-dimethylpyrazole (NNOH) and 3,5-dimethylpyrazole (NNH) act as N,O-polydentate anion ligands in coordinating the Cu(II) and Cd(II) centers. The structure of the cluster in the solid state was proved by XRD study and confirmed in the liquid state by UV-vis analysis. The XRD result supported the construction of two octahedral and one square pyramid geometries types around the four Cu(II) centers and only octahedral geometry around Cd(II) two centers. Interestingly, NNOH ligand acts as a tetra-µ3-oxo and tri-µ2-oxo ligand; meanwhile, the N-N in NNH acts as classical bidentate anion/neutral ligands. The interactions in the lattice were detected experimentally by the XRD-packing result and computed via Hirschfeld surface analysis (HSA). The UV-vis., FT-IR and Energy Dispersive X-ray (EDX), supported the desired double-open cubane cluster composition. The oxidation potential of the desired cluster was evaluated using a 3,5-DTB-catechol 3,5-DTB-quinone as a catecholase model reaction.

5.
Curr Drug Deliv ; 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33023446

RESUMO

AIM: - The synthesis of seven new antioxidant agents based on the combination of thiazole, pyridine, triazole and pyrazole moieties. - The studies of their antioxidant activity using DPPH reduction method. - The DFT analysis of the 7 ligands. - The docking study was also investigated. - The better binding affinity with α-cyclodextrin as best drug delivery system. BACKGROUND: - The screening of new antioxidant compounds and find the good mechanism for binding sites, with correlating between experience and computer theory. OBJECTIVES: - The synthesis of seven new antioxidant agents (nitrogen compounds) based on the combination of thiazole, pyridine, triazole and pyrazole moieties. - The studies of their antioxidant activity using DPPH reduction method. - The DFT analysis of the 7 synthesized ligands. - The docking study was also investigated by using the amino acids Ala167 and Arg172. - The better binding affinity with α-cyclodextrin as best drug delivery system. METHODS: - Chemistry: synthesis of ligands by condensation reaction - Application: Antioxidant activities using DPPH - Computational studies: using DFT and Docking - Correlation between all these properties. RESULT: - Chemistry: synthesis of 7 ligands by condensation reaction with 89% yield - Application: Antioxidant activities using DPPH reduction with a good value IC50=13.05 ± 3.73 µg/ml - Computational studies: using DFT (EHOMO and ELUMO) and Docking APX with the amino acids Ala167 and Arg172 compared to the ascorbic acid - Correlation between all these properties : α-cyclodextrin as best drug delivery system (better binding affinity than caffeic acid). CONCLUSION: For the drug delivery study, The ACD is best system for all the compounds due to the smallest cavity size which makes the binding affinities favorable and possible to prepare prospective nano-antioxidants.

6.
J Mol Liq ; 318: 114082, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32863490

RESUMO

Melatonin is a natural hormone from the pineal gland that regulates the sleep-wake cycle. We examined the structure and physico-chemical properties of melatonin using electronic structure methods and molecular-mechanics tools. Density functional theory (DFT) was used to optimise the ground-state geometry of the molecule from frontier molecular orbitals, which were analysed using the B3LYP functional. As its electrons interacted with electromagnetic radiation, electronic excitations between different energy levels were analysed in detail using time-dependent DFT with CAM-B3LYP orbitals. The results provide a wealth of information about melatonin's electronic properties, which will enable the prediction of its bioactivity. Molecular docking studies predict the biological activity of the molecules against the coronavirus2 protein. Excellent docking scores of -7.28, -7.20, and -7.06 kcal/mol indicate that melatonin can help to defend against the viral load in vulnerable populations. Hence it can be investigated as a candidate drug for the management of COVID.

7.
Molecules ; 25(9)2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-32403218

RESUMO

Three new tetradentate NNNS Schiff bases (L1-L3) derived from 2-(piperidin-4-yl)ethanamine were prepared in high yields. UV-Visible and FTIR spectroscopy were used to monitor the dehydration reaction between 2-(piperidin-4-yl)ethanamine and the corresponding aldehydes. Structures of the derived Schiff bases were deduced by 1H and 13C NMR, FTIR, UV-Vis, MS, EA, EDS, and TG-derived physical measurements. DFT/B3LYP theoretical calculations for optimization, TD-DFT, frequency, Molecular Electrostatic Potential (MEP), and highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) / were performed for L2. The in vitro antimicrobial activities of the three Schiff bases were evaluated against several types of bacteria by disk diffusion test using Gentamicin as the standard antibiotic. Schiff bases revealed good antioxidant activity by the DPPH method, and the IC50 values were compared to the Trolox standard. Pancreatic porcine lipase inhibition assay of the synthesized compounds revealed promising activity as compared to the Orlistat reference.

8.
Acta Crystallogr E Crystallogr Commun ; 76(Pt 3): 344-348, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32148873

RESUMO

The asymmetric unit of the title compound, C23H28O4, comprises two half-mol-ecules, with the other half of each mol-ecule being completed by the application of twofold rotation symmetry. The two completed mol-ecules both have a V-shaped appearance but differ in their conformations. In the crystal, each independent mol-ecule forms chains extending parallel to the b axis with its symmetry-related counterparts through C-H⋯π(ring) inter-actions. Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (65.4%), H⋯C/C⋯H (21.8%) and H⋯O/O⋯H (12.3%) inter-actions. Optimized structures using density functional theory (DFT) at the B3LYP/6-311 G(d,p) level are compared with the experimentally determined mol-ecular structures in the solid state. The HOMO-LUMO behaviour was elucidated to determine the energy gap.

9.
Int J Biol Macromol ; 150: 941-947, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31765758

RESUMO

Cactus pear peel as agricultural waste containing arabinogalactan and pectin was thermally treated at 300 °C for 4 h and the resultant carbonized material was applied as adsorbent for the removal of methylene blue dye as a model cationic dye. The prepared adsorbent was characterized by means FTIR for structural characterization, N2 physisoprtion measurements for texture properties, SEM and EDAX for morphological and elemental analysis. The characterization results clearly show that the prepared material is porous with several -OH and CO terminals. The point of zero charge was found to be 7 as detected by batch equilibrium method. The adsorption process was optimized in terms of pH values, contact time, initial dye concentration and temperature. The kinetic study indicated that the pseudo-second-order model can perfectly describe the investigated adsorption process; moreover, the equilibrium results were best fitted by Freundlich model. Furthermore, at pH 8.0, the adsorption capacity was achieved to the maximum value of methylene blue as 102 mg/g. Thermodynamic investigation showed that the adsorption process is spontaneous, endothermic in nature with higher entropy, while the activation energy calculations indicated a physisorption process. The obtained results showed the high potential of the bio-based adsorbent for removal of methylene blue from wastewater.

10.
Anal Chim Acta ; 1086: 55-65, 2019 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-31561794

RESUMO

Benefiting from the rich redox chemistry, high electrical conductivity and synergistic effect from two metal ions, the binary metal sulphides received tremendous attention in various applications. As a result, the MoS2-RuS2 nanomaterial was synthesized through the simple one-pot hydrothermal technique. The electrocatalytic activity of the as-synthesized nanomaterial was exploited towards the electrochemical detection of antibiotic drug sulphadiazine (SDZ). The electrocatalytic oxidation of the SDZ exhibited lowest anodic peak potential and ehanced anodic peak current rather than other modified electrodes. Notably, an excellent electrochemical performance with very lowest limit of detection (LOD) of 0.004 µM, appreciable linear range from 0.01 µM to 598.7 µM and high sensitivity (2.333 µA µM-1 cm-2) was obtained at MoS2-RuS2 modified electrode. Moreover, well anti-interfering property, good operational stability, repeatability and reproducibility was achieved. Facinatingly, the practicability of the modified electrode demonstrated in milk and human serum samples.


Assuntos
Antibacterianos/análise , Dissulfetos/química , Técnicas Eletroquímicas , Molibdênio/química , Rutênio/química , Sulfadiazina/análise , Sulfetos/química , Catálise , Eletrodos
11.
Ultrason Sonochem ; 58: 104664, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31450375

RESUMO

We have developed a graphitic carbon nitride covered vanadium oxide nanocomposite (V2O5@g-C3N4) by a simple sonochemical approach (50 kHz and 150 W/cm2). Furthermore, the morphology and chemical composition of the V2O5@g-C3N4 nanocomposite was carried out by X-rays diffractometry (XRD), transmission electron microscopy (TEM) and electrochemical impedance spectroscopy (EIS). Furthermore, the V2O5@g-C3N4 nanocomposite modified electrode was investigate electrochemical behavior of the anticancer drug. Compared with bare SPCE, V2O5/SPCE and g-C3N4/SPCE, V2O5@g-C3N4 modified SPCE showed highest current response towards anti-cancer drug (methotrexate). Furthermore, the modified sensor exhibits with a sharp peaks and wide linear range (0.025-273.15 µM) by using DPV with the sensitivity of 7.122 µA µM-1 cm-2. Notably, we have achieved a nanomolar detection limit (13.26 nM) for the DPV detection of methotrexate. Further, the practicability of the V2O5@g-C3N4 nanocomposite modified sensor can be used for real time sensing of methotrexate in drug and blood serum samples with good recover ranges. It has potential applications in routine analysis with high specificity, excellent reproducibility and good stability.

12.
Int J Mol Sci ; 13(5): 6279-91, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22754364

RESUMO

Novel hybrid xerogel materials were synthesized by a sol-gel procedure. n-octadecyltriethoxysilane was co-condensed with and without different cross-linkers using Q(0) and T(0) mono-functionalized organosilanes in the presence of n-hexadecylamine with different hydroxyl silica functional groups at the surface. These polymer networks have shown new properties, for example, a high degree of cross-linking and hydrolysis. Two different synthesis steps were carried out: simple self-assembly followed by sol-gel transition and precipitation of homogenous sols. Due to the lack of solubility of these materials, the compositions of the new materials were determined by infrared spectroscopy, (13)C and (29)Si CP/MAS NMR spectroscopy and scanning electron microscopy.


Assuntos
Aminas/química , Hidrocarbonetos/química , Compostos de Organossilício/síntese química , Tensoativos/química , Técnicas de Química Sintética , Reagentes para Ligações Cruzadas/química , Espectroscopia de Ressonância Magnética , Microscopia Eletrônica de Varredura , Dióxido de Silício/química , Espectrofotometria Infravermelho
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