Molecular simulation study of PAMAM dendrimer composite membranes

Amjad‐Iranagh, Sepideh; Golzar, Karim; Modarress, Hamid

doi:10.1007/s00894-014-2119-6

Cited by 21 publications

(8 citation statements)

References 92 publications

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“…The reported mass density is extracted from the interior region of the membrane wherein the density profile is relatively uniform. The mass density of the PSF membrane at 300 K is 1.14 g/cm 3 , which is consistent with previous simulation results …”

Section: Force Fields and Model Systemsmentioning

confidence: 99%

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Coupled Monte Carlo and Molecular Dynamics Simulations on Interfacial Properties of Antifouling Polymer Membranes

2021

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We use molecular simulation to study the wetting behavior of antifouling polymer-tethered membranes. We obtain the interfacial properties (e.g., contact angle) of water at various temperatures for five polymer membranes, including a base polysulfone (PSF) membrane and four other PSF membranes grafted with antifouling polymers (two poly(ethylene glycol) (PEG) tethers and two zwitterionic tethers). We implement a coupled Monte Carlo (MC)/molecular dynamics (MD) approach to determine the interface potentials of water on the membrane surfaces in an efficient manner. Within this method, short MC and MD simulations are performed in cycles to collect the surface excess free energy of a thin water film on polymer membrane surfaces. Simulation results show that the grafting of zwitterionic tethers provides a more significant enhancement in the hydrophilicity of the PSF membrane than that of the PEG tethers. Water completely wets the surface of zwitterionic polymer membranes.

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Section: Force Fields and Model Systemsmentioning

confidence: 99%

“…The mass density of the PSF membrane at 300 K is 1.14 g/cm 3 , which is consistent with previous simulation results. 53 Grafting of Antifouling Polymer Tethers. Following construction of the base PSF membrane model, we then graft antifouling polymer brushes onto the membrane surface to build the composite polymer membrane models.…”

Section: ■ Introductionmentioning

confidence: 99%

Coupled Monte Carlo and Molecular Dynamics Simulations on Interfacial Properties of Antifouling Polymer Membranes

2021

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“…The cut-off distance for the van der Waals interactions was 1.3 nm. The electrostatic interactions were computed with the particle mesh Ewald method 59 , 60 . The Trp and FA molecules were randomly placed in the simulation boxes.…”

Section: Methodsmentioning

confidence: 99%

Molecular dynamics simulation study of doxorubicin adsorption on functionalized carbon nanotubes with folic acid and tryptophan

Arabian

Amjad‐Iranagh

Halladj

2021

Sci Rep

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In this work, molecular dynamics (MD) simulation is used to study the adsorption of the anticancer drug, doxorubicin (DOX), on the wall or surface of pristine and functionalized carbon nanotubes (FCNTs) in an aqueous solution. Initially, the CNTs were functionalized by tryptophan (Trp) and folic acid (FA), and then the DOX molecules were added to the system. The simulation results showed that the drug molecules can intensely interact with the FCNTs at physiological pH. Furthermore, it was found that as a result of functionalization, the solubility of FCNTs in an aqueous solution increases significantly. The effect of pH variation on drug release from both pristine and FCNTs was also investigated. The obtained results indicated that in acidic environments due to protonation of functional groups (Trp) and as a result of repulsive interaction between the DOX molecule and functional groups, the release of DOX molecules from FCNT’s surface is facilitated. The drug release is also strongly dependent on the pH and protonated state of DOX and FCNT.

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“…58,59 To study the configuration and conformation of sulfoxonium ylide in CH 2 Cl 2 at 308 K, molecular dynamics (MD) simulations using the Forcite module as implemented in Materials Studio 19.1 software were performed. 60,61 The periodic boundary condition was used, with the size of the simulation box of 32.2 Å × 32.2 Å × 32.2 Å. Based on the experimental conditions of sulfoxonium ylide (0.1 mmol) and 4-dimethylaminopyridine (DMAP) (1 equiv) in 1.0 mL of CH 2 Cl 2 , the simulation system was constructed with the mole ratio of 1:1:156 for sulfoxonium ylide, DMAP, and CH 2 Cl 2 , respectively.…”

Section: ■ Computational Detailsmentioning

confidence: 99%

Mechanism and Selectivity of Cyclopropanation of 3-Alkenyl-oxindoles with Sulfoxonium Ylides Catalyzed by a Chiral N,N′-Dioxide–Mg(II) Complex

Meng

Wang

et al. 2021

J. Org. Chem.

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The mechanism and stereoselectivity of an asymmetric cyclopropanation reaction between 3-alkenyl-oxindole and sulfoxonium ylide catalyzed by a chiral N,N′dioxide−Mg(II) complex were explored using the B3LYP-D3(BJ) functional and the def2-TZVP basis set. The noncatalytic reaction occurred via a stepwise mechanism, with activation barriers of 21.6−23.5 kcal mol −1 . The C 2 −C α bond formed followed by the carbanion S N 2 substitution, constructing a three-membered ring in spiro-cyclopropyl oxindoles, accompanied by the release of dimethylsulfoxide. The electron-withdrawing Nprotecting t-butyloxy carbonyl (Boc) and acetyl (Ac) groups in isatin enhanced the local electrophilicity of the C2 atom and the repulsion between the two COPh groups in the reactants, contributing to high reactivity as well as good diastereoselectivity results. The N-Boc-3-phenacylideneoxindole coordinated to the chiral ligand (L-PiPr 2 ) in a bidentate fashion, forming a hexacoordinate-Mg(II) complex as the reactive species. The origin of enantioselectivity was from the shielding effect of 2,6-diisopropylphenyl groups in the ligand toward the si-face of oxindole. The repulsion between the SO(CH 3 ) 2 and COPh groups in 3-alkenyl-oxindole and the neighboring ortho-iPr group in the ligand directed the re-face of ylide to attack the re-face of oxindole preferably, contributing to the high diastereoselectivity of the product. A metal-ion−ligand matching relationship was important for a good asymmetric induction effect of the chiral N,N′-dioxide−metal catalyst. A large chiral cavity in the Zn(II) catalyst weakened the shielding effect of 2,6-diisopropylphenyl groups in the ligand toward the prochiral face of oxindole, leading to inferior enantioselectivity observed in the experiment.

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Molecular simulation study of PAMAM dendrimer composite membranes

Cited by 21 publications

References 92 publications

Coupled Monte Carlo and Molecular Dynamics Simulations on Interfacial Properties of Antifouling Polymer Membranes

Coupled Monte Carlo and Molecular Dynamics Simulations on Interfacial Properties of Antifouling Polymer Membranes

Molecular dynamics simulation study of doxorubicin adsorption on functionalized carbon nanotubes with folic acid and tryptophan

Mechanism and Selectivity of Cyclopropanation of 3-Alkenyl-oxindoles with Sulfoxonium Ylides Catalyzed by a Chiral N,N′-Dioxide–Mg(II) Complex

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