scholarly journals Design and Molecular Modeling of Abiraterone-Functionalized Gold Nanoparticles

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 641 ◽  
Author(s):  
Elżbieta Stolarczyk ◽  
Marta Łaszcz ◽  
Andrzej Leś ◽  
Marek Kubiszewski ◽  
Krzysztof Kuziak ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Density Functional ◽  
Essential Feature ◽  
Physicochemical Characterization ◽  
Basic Study ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Charged Nanoparticles ◽  
Pharmacologically Active

The aim of our work was the synthesis and physicochemical characterization of a unique conjugate consisting of gold nanoparticles (AuNPs) and a pharmacologically active anticancer substance abiraterone (AB). The direct coupling of AB with gold constitutes an essential feature of the unique AuNPs–AB conjugate that creates a promising platform for applications in nanomedicine. In this work, we present a multidisciplinary, basic study of the obtained AuNPs–AB conjugate. Theoretical modeling based on the density functional theory (DFT) predicted that the Aun clusters would interact with abiraterone preferably at the N-side. A sharp, intense band at 1028 cm−1 was observed in the Raman spectra of the nanoparticles. The shift of this band in comparison to AB itself agrees well with the theoretical model. AB in the nanoparticles was identified by means of electrochemistry and NMR spectroscopy. The sizes of the Au crystallites measured by XRPD were about 9 and 17 nm for the nanoparticles obtained in pH 7.4 and 3.6, respectively. The size of the particles as measured by TEM was 24 and 30 nm for the nanoparticles obtained in pH 7.4 and pH 3.6, respectively. The DLS measurements revealed stable, negatively charged nanoparticles.

Density functional theory (DFT) calculations on the structures and stabilities of [CnO2n+1]2– and [CnO2n+1]X2 polycarbonates containing chainlike (CO2)n units (n = 2–6; X = H or Li)

2011 ◽  
Vol 89 (6) ◽  
pp. 671-687 ◽  
Author(s):  
Pablo J. Bruna ◽  
Friedrich Grein ◽  
Jack Passmore
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Ion Pairs ◽  
Dicarboxylic Acids ◽  
Polarizable Continuum Model ◽  
Weakly Bound ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Weakly Bound Complexes

The structures and stabilities of chainlike (CO2)n (n = 2–6) polycarbonates, where adjacent C atoms are linked by C–O–C bonds, were investigated at the density functional theory (DFT) level (B3PW91/6–311G(2d,p)), including dicarboxylic dianions, [CnO2n+1]2–, and the corresponding acids, [CnO2n+1]H2, and Li salts, [CnO2n+1]Li2. At equilibrium, the most stable systems have Cs, C2, or C2v symmetries. In the gas phase, these dianions are generally metastable with respect to spontaneous ejection of one electron, yet in the presence of counterions they become stabilized, for example, as [CnO2n+1]2–(Li+)2 ion pairs. [CnO2n+1]2– linkages are also stabilized as dicarboxylic acids, [CnO2n+1]H2; we find the latter to have equilibrium conformations of higher symmetry than previously reported in the literature. To the best of our knowledge, none of the [CnO2n+1]X2 (X = Li or H) compounds with n ≥ 2 have been reported in the experimental literature (albeit, the alkyl esters C2O5R2 and C3O7R2 are commercially available). All CO bonds in C2O5X2 to C6O13X2 have single- to double-bond character (≈140–118 pm), indicating that the [CnO2n+1] moieties are held together by strong chemical forces (in contrast to the weakly bound complexes (CO2)n and (CO2)n–, n > 1). Vibrational frequencies were calculated to ensure all conformations were true minima. The IR and Raman intensities show that the high intensity C=O stretching modes (1750 ± 100 cm–1) will help in the spectral characterization of these compounds. Solvation calculations using the polarizable continuum model (PCM) find that C2O52– can be formed via CO32– + CO2 as well as CO3–[Formula: see text], each reaction having ΔG298 < 0 in practically all solvents. This result confirms the experimentally observed large solubility of CO2(g) in molten carbonates, CO3M2 (M = Li, Na, or K). In contrast, starting with n = 2, the reactions [CnO2n+1]2– + CO2 do not proceed spontaneously in any solvent (ΔG298 > 0).

scholarly journals Structural characterization of kaempferol: a spectroscopic and computational study

2019 ◽  
Vol 38 (1) ◽  
pp. 49 ◽  
Author(s):  
Dejan Milenković ◽  
Jasmina M Dimitrić Marković ◽  
Dušan Dimić ◽  
Svetlana Jeremić ◽  
Dragan Amić ◽  
...  
Keyword(s):  
Density Functional ◽  
Computational Study ◽  
Chemical Shifts ◽  
Absolute Error ◽  
Nbo Analysis ◽  
Basis Set ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Spectroscopic Characteristics

Calculations based on the density functional theory, with the B3LYP functional and the 6-311++G(d,p) basis set, were performed with the aim of confirming the molecular structure and spectroscopic characteristics of kaempferol, a naturally occurring flavonoid molecule. The electronic structure of kaempferol was examined using NBO analysis. The assigning of the experimentally obtained IR and Raman spectra was performed after the best-fit-based comparison with theoretical spectra. The 13C and 1H NMR experimental spectra were related to the theoretically obtained values of the chemical shifts determined by the GIAO method. The correlation coefficient and the average absolute error values proved B3LYP-D3 to be an adequate method in describing the NMR parameters of kaempferol. Molecular docking analysis was carried out in order to identify the potency of inhibition of the title molecule against human procalcitonin. The inhibition activity was obtained for 10 conformations of ligand inside the protein.

Density Functional Theory Investigation and Detonation Characterization of DNPDNAZ

2014 ◽  
Vol 997 ◽  
pp. 264-267
Author(s):  
Hong Ya Li ◽  
Tian Tian Zhang
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Dft Method ◽  
Detonation Pressure ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Equivalent Equation ◽  
Molecular Reactivity ◽  
Density Results

N-2’,4’-dinitrophenyl-3,3-dinitroazetidine (DNPDNAZ) is an important derivative of 3,3-dinitroazetidine (DNAZ). The density functional theory (DFT) method of the Amsterdam density functional (ADF) was used to calculate the geometry and frequencies. The detonation velocity (D) and detonation pressure (P) of DNPDNAZ were estimated using the nitrogen equivalent equation according to the experimental density. Results showed that the initial decomposition step of DNPDNAZ is the loss of NO2from C2 and N1 is the point of molecular reactivity,DandPare 7364.42 m·s-1and 23.75 GPa, respectively.

COMPUTATIONAL CHARACTERIZATION OF THE ELUSIVE C-CLUSTER OF CARBON MONOXIDE DEHYDROGENASE

2008 ◽  
Vol 07 (04) ◽  
pp. 473-484 ◽  
Author(s):  
ZEXING CAO ◽  
YIRONG MO
Keyword(s):  
Carbon Monoxide ◽  
Density Functional ◽  
Structural Features ◽  
Oxidation Of Co ◽  
Functional Theory ◽  
Structural Conversion ◽  
Redox States ◽  
The Density Functional Theory ◽  
Key Species

Structural features of the C-cluster of carbon monoxide dehydrogenases at different redox states have been investigated by the density functional theory. The key species involved in the oxidation of CO at clusters C , Cox, Cred1, Cred2, and Cint, have been specified. Computational results indicate that the CO -induced transformation of the [Ni–4Fe–5S] cluster C into the [Ni–4Fe–4S] cluster is facile energetically, and such structural conversion at the active site may reconcile different reported crystal structures of cluster C. The coordination of CO to the Ni site of the reduced C-cluster (Cred1) will enhance its electron accommodation ability and makes Fe1 more accessible to other substrates, which lends support to the assumption that Cred1 is a ready state for CO oxidation. On the basis of calculations, the possible catalytic cycle for the oxidation of CO at cluster C was proposed.

Experimental and Theoretical Characterization of the 3D-Dopants Bias on the H Desorption of Mg Hydrides

2007 ◽  
Vol 555 ◽  
pp. 349-354 ◽  
Author(s):  
Fabrizio Cleri ◽  
Massimo Celino ◽  
Amelia Montone ◽  
Ennio Bonetti ◽  
Luca Pasquini
Keyword(s):  
Density Functional ◽  
Microstructural Characterization ◽  
Hydrogen Desorption ◽  
Functional Theory ◽  
3D Metals ◽  
The Density Functional Theory ◽  
Composite Microstructure ◽  
Structure Calculations ◽  
Theoretical Results

Extensive electronic structure calculations, based on the density-functional theory, are used to characterize the equilibrium properties and the behaviour under pressure of MgH2. Moreover, substitutional solid solutions for several 3d metals (Fe, Ni, Ti, Al, Pd, Co, etc.) in MgH2 are characterized by computing both relaxed structures and solution energies. Theoretical results are combined with experimental results on samples synthesized by ball milling. MgH2 was milled with 10 wt.% of 3d metals followed by microstructural characterization and hydrogen desorption behaviour. Good correlation between theoretical solution energies and experimental desorption temperatures reveals a general trend in these systems. A few notable exceptions can be detected, which can be explained in terms of peculiarities in the experimental composite microstructure.

scholarly journals Synthesis and Characterization of Cu(I)-Folic Acid Complex A Theoretical and Experimental Study

2016 ◽  
Vol 13 (2) ◽  
pp. 121-127
Author(s):  
Baghdad Science Journal
Keyword(s):  
Folic Acid ◽  
Density Functional ◽  
Mulliken Charge ◽  
Mulliken Population ◽  
Acid Complex ◽  
Functional Theory ◽  
Acid Ligand ◽  
The Density Functional Theory ◽  
Homo Lumo

Copper (I) complex containing folic acid ligand was prepared and characterized on the basis of metal analyses, UV-VIS, FTIR spectroscopies and magnetic susceptibility. The density functional theory (DFT) as molecular modeling calculations was used to determine the donor atoms of folic acid ligand which appear clearly at oxygen atoms binding to hydrogen. Detection of donation sights is supported by theoretical parameters such as geometry, mulliken population, mulliken charge and HOMO-LUMO gap obtained by DFT calculations.

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