DFT Study of Adsorption of Diazinon,Hinosan, Chlorpyrifos and Parathion Pesticides on the Surface of B36N36 Nanocage and Its Fe Doped Derivatives as New Adsorbents

In this work, we used density functional theory with the Tkatchenko and Scheffler method to investigate the adsorption of diazinon, hinosan, chlorpyrifos, and parathion organophosphorus pesticides on the surface of B₃₆N₃₆ nanocage and its Fe doped derivatives. The assessments revealed that van der Waals interaction is a key factor in organophosphate adsorption on the surface of these nanocages as well as overlapping. The results of Fukui indices and atomic partial charges calculations indicated that these pesticides and nanocages act as nucleophile and electrophile, respectively, and the adsorption sites of all four organophosphates on these nanocages are thiophosphate groups, as well as the aromatic ring in diazinon, and the nitro group in parathion. In addition, the calculated adsorption energies yielded the best result for diazinon, and the best Fe doped B₃₆N₃₆ derivative for adsorbing organophosphates in aqueous solution is the one in which Fe atom is located in the boron position of the square ring of B₃₆N₃₆.     

Hollow boron nitride (BN) nanocages and BN-nanocage-encapsulated nanocrystals

Hollow boron nitride (BN) nanocages (nanospheres, image on the left) and BN-nanocage-encapsulated GaN nanocrystals (right) have been synthesized by using a homemade B-N-O precursors. The as-prepared BN hollow nanocages have typically spherical morphologies with diameters ranging from 30 to 200 nm. The nanocages have crystalline structures. Peanutlike nanocages with double walls have also been observed; their internal space is divided into seperated compartments by the internal walls. The method is extended to sheathe nanocrystals with BN nanocages; BN-shell/GaN-core nanostructures have been successfully fabriacted. The method may be generally applicable to the fabrication BN-sheathed nanocrystals.     

Penicillamine functionalized B12N12 and B12CaN12 nanocages act as potential inhibitors of proinflammatory cytokines: A combined DFT analysis,ADMET and molecular docking study

The adsorption of penicillamine (PCA) on pure B₁₂N₁₂ and B₁₂CaN₁₂ nanocages in aqueous and chloroform solvents has been evaluated using density functional theory (DFT) calculations. The interaction of PCA on B₁₂N₁₂ nanocages is chemisorption through its four nucleophilic sites: amine, carbonyl, hydroxyl and thiol. The most stable adsorption configuration was achieved when zwitterionic PCA adsorbs via its carbonyl group in water with value of ?1.723 eV, in contrast, when neutral PCA adsorbs via its amine group in chloroform with value of ?1.68 eV. Intercalated calcium ion within B₁₂N₁₂ nanocage (B₁₂CaN₁₂) was shown to attract PCA onto nanocage surface, resulting in higher solubility and adsorption energy after their complexation in water and chloroform. The adsorption of multiple PCA molecules from their amine and carbonyl groups on pure and B₁₂CaN₁₂ nanocages were also evaluated where two and three molecules can be chemisorbed on boron atoms of the nanocage surfaces with the adsorption energy per PCA reduces slightly with the increasing the amount of drugs due to the curvature effects. Molecular docking study indicates that PCA from its NH₂ group on B₁₂CaN₁₂ nanocage has the best binding affinity and inhibition potential of tumor necrosis factor-alpha (TNF-α) and Interleukin-1 (IL-1) receptors as compared with the other adsorption systems. Molecular docking and ADMET analysis displayed that the chosen compounds pass Lipinski Rule and have appropriate pharmacokinetic features suitable as models for developing anti-inflammatory agents.     

Molecular docking evaluation of celecoxib on the boron nitride nanostructures for alleviation of cardiovascular risk and inflammatory

Celecoxib (CXB) is a nonsteroidal anti-inflammatory drug (NSAID) that can be used to treat rheumatoid arthritis and ischemic heart disease. In this research, density functional theory (DFT) and molecular docking simulations were performed to study the interaction of boron nitride nanotube (BNNT) and boron nitride nanosheet (BNNS) with CXB and its inhibitor effect on pro-inflammatory cytokines. The calculated adsorption energies of CXB with the BNNT were determined in aqueous phase. The results revealed that adsorption of CXB molecule via its SO₂ group on BNNT is thermodynamically favored than the NH₂ and CF₃ groups in the solvent environment. Adsorption of CXB on BN nanomaterials are weak physisorption in nature. This can be attributed to the fact that both phenyl groups in CXB are not on the same plane and require significant activation energies for conformational changes to obtain greater H-$\pi$ interaction. Both BNNT and BNNS materials had huge sensitivity in electronic change and short recovery time during CXB interaction, thus having potential as molecular sensor and biomedical carrier for the delivery of CXB drug. IL-1A and TNF-α were implicated as vital cytokines in diverse diseases, and they have been a validated therapeutic target to manage cardiovascular risk in patients with inflammatory bowel disease. A molecular docking simulation confirms that the BNNT loaded CXB could inhibit more pro-inflammatory cytokines including IL-1A and TNF-α receptors as compared to BNNS loaded to CXB.     

杀虫剂二嗪农杀虫剂二嗪农、克瘟散、毒死蜱和对硫磷在B_(36)N_(36)纳米笼及其掺Fe衍生物表面的吸附的DFT研究（英文）

In this work,we used density functional theory with the Tkatchenko and Scheffler method to investigate the adsorption of diazinon,hinosan,chlorpyrifos,and parathion organophosphorus pesticides on the surface of B36N36nanocage and its Fe doped derivatives.The assessments revealed that van der Waals interaction is a key factor in organophosphate adsorption on the surface of these nanocages as well as overlapping.The results of Fukui indices and atomic partial charges calculations indicated that these pesticides and nanocages act as nucleophile and electrophile,respectively,and the adsorption sites of all four organophosphates on these nanocages are thiophosphate groups,as well as the aromatic ring in diazinon,and the nitro group in parathion.In addition,the calculated adsorption energies yielded the best result for diazinon,and the best Fe doped B_(36)N_(36) derivative for adsorbing organophosphates in aqueous solution is the one in which Fe atom is located in the boron position of the square ring of B_(36)N_(36).     

Molecular modeling investigation of adsorption of Zolinza drug on surfaces of the B12N12 and Al12N12 nanocages

Structural Chemistry - In the current work, the adsorption of Zolinza (ZOL) drug on B12N12 and Al12N12 nanocages was investigated using density functional theory (DFT) and time-dependent DFT...     

Oxygen adsorption characteristics on hybrid carbon and boron‐nitride nanotubes

In this work, first‐principles density functional theory (DFT) is used to predict oxygen adsorption on two types of hybrid carbon and boron‐nitride nanotubes (CBNNTs), zigzag (8,0), and armchair (6,6). Although the chemisorption of O₂ on CBNNT(6,6) is calculated to be a thermodynamically unfavorable process, the binding of O₂ on CBNNT(8,0) is found to be an exothermic process and can form both chemisorbed and physisorbed complexes. The CBNNT(8,0) has very different O₂ adsorption properties compared with pristine carbon nanotubes (CNTs) and boron‐nitride nanotube (BNNTs). For example, O₂ chemisorption is significantly enhanced on CBNNTs, and O₂ physisorption complexes also show stronger binding, as compared to pristine CNTs or BNNTs. Furthermore, it is found that the O₂ adsorption is able to increase the conductivity of CBNNTs. Overall, these properties suggest that the CBNNT hybrid nanotubes may be useful as a gas sensor or as a catalyst for the oxygen reduction reaction. © 2014 Wiley Periodicals, Inc.     

Adsorption of Fe（CO）4 on the Sidewall of Boron Nitride Nanotubes： A Periodic DFT Study

The adsorption of Fe（CO）4 on various types of boron nitride nanotubes （BNNTs） areinvestigated by employing density functional theory. Our results indicate that Fe（CO）4 prefers to adsorb on the top of nitrogen atom via Fe atom, and the electronic property analysis indicates that the adsorption of Fe（CO）4 can reduce the band-gap of BNNTs.     

Phase transformation of boron nitride under hypothermal conditions

Phase transformation among different boron nitride (BN) phases in hydrothermal solution was investigated. It was found that hexagonal boron nitride (hBN) firstly formed in the solution at relatively low temperature (i.e., 220 °C). After that, a spot of hBN began to transform into wurtzite boron nitride (wBN) and cubic boron nitride (cBN) at 230 °C. More and more hBN converted into wBN and cBN with the increase in temperature, and this transformation process completed at 300 °C. In this paper, we have explained the mechanism of the above phase transformation by using a reported “puckering mechanism”.     

High-Resolution 14N Solid-State NMR Spectroscopy

Even without expensive isotope enrichment, it is possible to obtain nitrogen NMR parameters in the solid state. The isotropic chemical shifts in hexagonal and cubic boron nitride, and for the hexagonal modification also the quadrupole coupling, can thus be obtained for the first time. The recorded ¹⁴N MAS NMR spectrum (28.809 MHz) of hexagonal boron nitride is shown on the right.     

Surface complexation of condensed phosphate to aluminum hydroxide: an ATR-FTIR spectroscopic investigation

Two model compounds, sodium pyrophosphate (pyro-P) and sodium tripolyphosphate (tripoly-P), were employed to elucidate the binding mechanisms of condensed phosphate on aluminum hydroxide by utilizing attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. Peak assignments for the condensed phosphates in the solution phase and those adsorbed on the surface of aluminum hydroxide were made. Electron delocalization and polarization were employed to explain the peak shifts and the complexation of condensed phosphate with aluminum hydroxide. The tripoly-P and pyro-P were adsorbed on aluminum hydroxide by forming inner-sphere complexes. The adsorbed condensed phosphates were deprotonated in the pH range from 4 to 10. Monodentate, bidentate, and binuclear complexes were formed when pyro-P was adsorbed on aluminum hydroxide, while monodentate and binuclear complexes were formed when tripoly-P was adsorbed. Based on the FTIR data, we proposed that when either bidentate or binuclear complexes were formed, the two oxygen atoms participating in the complexation with aluminum hydroxide could not be originated from the same terminal phosphate moiety. The AlO bond formed in the complexation of pyro-P or tripoly-P with aluminum hydroxide (AlPO(-3)) was not as strong as the HO bond in terminal HPO(-3). The bridging PO(-2) of tripoly-P did not coordinate with aluminum hydroxide. The real-time ATR-FTIR study on condensed phosphate adsorption revealed that a long contact time between condensed phosphates and aluminum hydroxide particles can result in a transformation of an initially formed species into a thermodynamically more stable phase.     

DFT based insights into reactivity descriptors of encapsulated B<Subscript>24</Subscript>N<Subscript>24</Subscript> nanocages

The purpose of this study is to probe the DFT based chemical reactivity parameter, electrophilicity index as a possible molecular engineering of endohedral BN-nanocages. The structure and electronic properties of endohedral boron nitride nanocages have been investigated as a function of alkali atom inside the nanocage using density functional theory. We have calculated and analyzed basic characteristic related to the reactive behavior, such as HOMO–LUMO band gap, chemical hardness, chemical potential, vertical electron affinity, and vertical ionization potential, as well as the global electrophilicity index, ω(I, A) of the encapsulated B₂₄N₂₄ nanocages. We also investigated the MQZVP basis set effect on total electronic energy of the clusters.     

Hydrogen adsorption on carbon-doped boron nitride nanotube

The adsorption of atomic and molecular hydrogen on carbon-doped boron nitride nanotubes is investigated within the ab initio density functional theory. The binding energy of adsorbed hydrogen on carbon-doped boron nitride nanotube is substantially increased when compared with hydrogen on nondoped nanotube. These results are in agreement with experimental results for boron nitride nanotubes (BNNT) where dangling bonds are present. The atomic hydrogen makes a chemical covalent bond with carbon substitution, while a physisorption occurs for the molecular hydrogen. For the H(2) molecule adsorbed on the top of a carbon atom in a boron site (BNNT + C(B)-H(2)), a donor defect level is present, while for the H(2) molecule adsorbed on the top of a carbon atom in a nitrogen site (BNNT + C(N)-H(2)), an acceptor defect level is present. The binding energies of H(2) molecules absorbed on carbon-doped boron nitride nanotubes are in the optimal range to work as a hydrogen storage medium.     

Adsorption properties of hydrazine on pristine and Si-doped Al12N12 nano-cage

The interaction of hydrazine (N₂H₄) molecule with pristine and Si-doped aluminum nitride (Al₁₂N₁₂) nano-cage was investigated using the density functional theory calculations. The adsorption energy of N₂H₄ on pristine Al₁₂N₁₂ in different configurations was about –1.67 and –1.64 eV with slight changes in its electronic structure. The results showed that the pristine nano-cage can be used as a chemical adsorbent for toxic hydrazine in nature. Compared with very low sensitivity between N₂H₄ and Al₁₂N₁₂ nano-cage, N₂H₄ molecule exhibits high sensitivity toward Si-doped Al₁₂N₁₂ nano-cage so that the energy gap of the Si-doped Al₁₂N₁₂ nano-cage is changed by about 31.86% and 37.61% for different configurations in the Si_Al model and by about 26.10% in the Si_N model after the adsorption process. On the other hand, in comparison with the Si_Al model, the adsorption energy of N₂H₄ on the Si_N model is less than that on the Si_Al model to hinder the recovery of the nano-cage. As a result, the Si_N Al₁₂N₁₁ is anticipated to be a potential novel sensor for detecting the presence of N₂H₄ molecule.     

Oxygen Functionalization of Hexagonal Boron Nitride on Ni(111)

The interaction of single-layer hexagonal boron nitride (h-BN) on Ni(111) with molecular oxygen from a supersonic molecular beam led to a covalently bonded molecular oxygen species, which was identified as being between a superoxide and a peroxide. This is a rare example of an activated adsorption process leading to a molecular adsorbate. The amount of oxygen functionalization depended on the kinetic energy of the molecular beam. For a kinetic energy of 0.7 eV, an oxygen coverage of 0.4 ML was found. Near-edge X-ray adsorption fine structure (NEXAFS) spectroscopy revealed a stronger bond of h-BN to the Ni(111) substrate in the presence of the covalently bound oxygen species. Oxygen adsorption also led to a shift of the valence bands to lower binding energies. Subsequent temperature-programmed X-ray photoelectron spectroscopy revealed that the oxygen boron bonds are stable up to approximately 580 K, when desorption, and simultaneously, etching of h-BN set in. The experimental results were substantiated by density functional theory calculations, which provided insight to the adsorption geometry, the adsorption energy and the reaction pathway.     

Hydrogen adsorption on zigzag (8,0) boron nitride nanotubes

The chemical adsorption of H atoms on an (8,0) zigzag boron nitride nanotube is studied using the density functional theory with the supercell method. One to four H atoms per 32 B and 32 N are considered. The results show that H atoms prefer to adsorb on the top sites of adjacent B and N atoms to form an armchair chain along the tube axis. An even-odd oscillation behavior of the adsorption energy of H atoms on the tube is found, and the average adsorption energy of even H atoms is obviously bigger than that of odd H atoms. The results can be understood with the frontier orbital theory. Based on this adsorption behavior, several high-symmetric structures of H adsorbed boron nitride nanotubes with 50% and 100% coverages are studied. The pairs of lines' pattern with 50% coverage has the biggest average adsorption energy per H(2) among the chosen configurations, corresponding to approximately 4 wt % hydrogen storage.     

Effect of molecular packing on adsorption and micelle formation of a homologous cationic surfactant mixture of hexadecyltrimethylammonium bromide and dodecyltrimethylammonium bromide

The surface tension of an aqueous solution of a hexadecyltrimethylammonium bromide (HTAB) and dodecyltrimethylammonium bromide (DTAB) mixture was measured as a function of the total molality and the composition of DTAB at 298.15 K under atmospheric pressure. The phase diagrams of adsorption and micelle formation were constructed and the excess Gibbs energy was evaluated by analyzing the phase diagrams thermodynamically. Both the excess Gibbs energy in the adsorbed film and the excess surface area are negative; therefore the mutual interaction between HTAB and DTAB is said to be stronger than that between the same species and is enhanced with increasing adsorption. By combining the results with those obtained in previous studies, we claimed that DTAB molecules can use effectively the space among the hydrocarbon chains of HTAB molecules and their polar head groups take a staggered arrangement at the surface so as to reduce the electrostatic repulsion. Consequently the dispersion force between hydrophobic chains becomes stronger. Furthermore, the comparison of the excess Gibbs energy in the adsorbed film with that in the micelle shows that the staggered arrangement of molecules is not necessary in the spherical micelle.     

Enhanced thermal conductivity of epoxy–matrix composites with hybrid fillers

The results of thermal conductivity study of epoxy–matrix composites filled with different type of powders are reported. Boron nitride and aluminum nitride micro‐powders with different size distribution and surface modification were used. A representative set of samples has been prepared with different contents of the fillers. The microstructure was investigated by SEM observations. Thermal conductivity measurements have been performed at room temperature and for selected samples it was also measured as a function of temperature from 300 K down to liquid helium temperatures. The most spectacular enhancement of the thermal conductivity was obtained for composites filled with hybrid fillers of boron nitride–silica and aluminum nitride–silica. In the case of sample with 31 vol.% of boron nitride–silica hybrid filler it amounts to 114% and for the sample with 45 vol.% of hybrid filler by 65% as compared with the reference composite with silica filler. However, in the case of small aluminum nitride grains application, large interfacial areas were introduced, promoting creation of thermal resistance barriers and causing phonon scattering more effective. As a result, no thermal conductivity improvement was obtained. Different characters of temperature dependencies are observed for hybrid filler composites which allowed identifying the component filler of the dominant contribution to the thermal conductivity in each case. The data show a good agreement with predictions of Agari‐Uno model, indicating the importance of conductive paths forming effect already at low filler contents. Copyright © 2014 John Wiley & Sons, Ltd.     

New phases of sp2-bonded boron nitride: the 12R and 24R polytypes

sp2-Bonded polytypes of graphite-like boron nitride are evidenced in the approximately twin-related bicrystal-like BN nanofibres synthesized by a high-temperature substitution reaction between carbon nanofibres and boron oxides in N2 atmosphere; the material shows a main 12R phase of A'ABC/C'CAB/B'BCA packing and a minor 24R phase with an A'ABC/BB'C'A'/C'CAB/ ... packing sequence.     

Quantum-chemical study on the effect of Lewis acid centers in a poly(ethylene oxide)-based solid electrolyte

Quantum-chemical calculations on borate and aluminate esters have been performed to study the effect of a Lewis acid center on the ion complexation in a poly(ethylene oxide)-based solid electrolyte. The preferred conformations of the investigated model molecules have been determined. Stabilization energies for Li+ and ClO4- ions complexed at the boron or aluminum center have been calculated. The results reveal that the stabilization of the perchlorate ion at the boron center is mainly due to the interactions with CH2 and CH3 groups and suggest much stronger binding of the anion to the aluminum atom.