Intercalation Complexes Research Articles

Study on the preparation and anticorrosive performance of silica/modified kaolin/epoxy resin composite coating

Abstract A silica/aminated kaolin (SiO2@AK) composite was prepared by modifying kaolin and loading silica, using intercalation complex method and sol–gel method. Quantitative composites were dispersed in epoxy resin to obtain a silica/aminated kaolin/epoxy resin composite coating (SiO2@AK/EP) on stainless steel. The results showed that the thickness of the dry coating was approximately 110 ± 10 μm, and the surface was flat without evident agglomeration. As the SiO2@AK composite was introduced, the water contact angle increased from 40° to 88°, the average surface roughness of the prepared composite coating was reduced from 10.3 nm to 3.19 nm, and the corrosion current decreased by nearly three orders of magnitude. After the coating was soaked in 3.5 wt% NaCl solution for 30 days, the impedance modulus of the composite coating remained above 2.511 × 109 Ω cm2, reflecting that the introduction of the composite could effectively improve the anticorrosion property of the epoxy resin.

Application of Novel Ruthenium (II) Polypyridyl Complexes as Robust DNA Probes, Optical Material and Antimicrobials-An Experimental and DFT Approach.

The nature of the interaction of DNA with heteroleptic Ruthenium (II) Polypyridyl complexes of the type [Ru (A)2TPIP]2+, where TPIP = 2-(1-p-tolyl-1H pyrazol-4 -yl)-1H-imidazo [4, 5-f[1. 10] phenanthroline and A = 1,10 phenanthroline (1),4,4'-dimethyl-1,10-ortho Phenanthroline (2),2,2' - bipyridine(3) and 4, 4' dimethyl 2, 2'- bipyridine (4), has been investigated by experimentaland molecular docking approaches. The order of the DNA binding affinities of the synthesised complexes is 1 > 2 > 3 > 4. The findings imply that the unsubstitutedcomplex has a better affinity to bind with DNA than the substituted (dmp and dmb) emphasizing the significance of the auxiliary ligand. Additionally, as the medium's ionic strength drops, the DNA/Ru ratio rises, or when water is displaced by glycerol, the intercalation of complexes into DNA increases. DFT calculations at the B3LYP/LANL2MBlevel was used for molecular geometry (Ground State) and electronic characteristic calculations. The HOMO-LUMO gap of the Ru [II]complex is less than the intercalator and hence kinetically labile. Among the complexes, the bpy complex has shown utmost non-linear optical properties (α = -153.9099 10-24esuand β = 3.8498 10-30esu). The docking study shows the significance of the Metal-intercalator's shorter length may increase DNA binding affinity. This study divulges that the Ruthenium (II) polypyridyl complexes bind to DNA preponderantly by intercalation supporting Viscosity studies. All the complexes have a considerable attraction for guanine. The standarddiskdiffusion method reveals that complexes (1,2,3 and 4) have good antibacterial activity.

In situ confined growth of Cu2-xSe nanoparticles in highly defective nitrogen-doped carbon for high-rate sodium-ion battery anodes

Transition metal selenides are considered as hopeful anode materials for sodium-ion battery (SIB) due to the high specific capacity and rich reserves in nature. However, the inherent low conductivity of these anode materials, as well as the inevitable volume expansion and structural collapse during cycling, result in their poor rate performance and cycling stability. Herein, a universal selenization-co-carbonization strategy is proposed to synthesize Cu2-xSe nanoparticles in-situ confined in highly defective nitrogen-doped carbon (Cu2-xSe@NC) with superior architectural features, which involves simultaneous selenization and carbonization procedure of octahedral metal–organic framework (Cu-BTC) precursor. The nitrogen-doped carbon matrix stabilizes/confines the Cu2-xSe nanoparticles to prevent their agglomeration and volume expansion during cycling while endowing high electrical conductivity to the hybrid materials. As anode for SIBs, the Cu2-xSe@NC exhibits a high reversible capacity of 340 mAh/g at 0.1 A/g with a high initial coulombic efficiency of 70 %, superior rate performance (capacity retention of 82.4 % from 0.02 to 5 A/g), and long-cycle durability. The ex-situ XRD and HRTEM techniques confirmed that Cu2-xSe undergoes complex intercalation and crystal evolution accompanied by reversible intermediate phases (NaCuSe and Na2Se) transformation during charge/discharge cycle. First-principles calculations and in-situ EIS confirmed that the intercalation of Na+ can greatly reducing the energy band gap and improving the electrical conductivity of Cu2-xSe@NC, thereby achieving excellent rate performance. Moreover, the Cu2-xSe@NC anode is also evaluated by matching with Na3V2(PO4)3 cathode to assemble a full SIB, which can provide high initial capacity and capacity retention, revealing its potential for practical application.

Molecular Simulations of Hydrogen Sorption in Semicrystalline High-Density Polyethylene: The Impact of the Surface Fraction of Tie-Chains.

The modeling of the barrier properties of semicrystalline polymers has gained interest following the possible application of such materials as protective liners for the safe supply of pressurized hydrogen. The mass transport in such systems is intimately related to the complex intercalation between the crystal and amorphous phases, which was approached in this work through an all-atom representation of high-density polyethylene structures with a tailored fraction of amorphous-crystalline connections (tie-chains). Simulations of the polymer pressure-volume-temperature data and hydrogen sorption were performed by means of molecular dynamics and the Widom test particle insertion method. The discretization of the simulation domains of the semicrystalline structures allowed us to obtain profiles of density, degree of order, and gas solubility. The results indicated that the gas sorption in the crystalline regions is negligible and that the confinement of the amorphous phase between crystals induces a significant increase in density and a drop in the sorption capacity, even in the absence of tie-chains. Adding ties between the crystal and the amorphous phase results in further densification, an increase of the lamella tilt angle, and a decrease in the degree of crystallinity and hydrogen sorption coefficient, in agreement with several literature references.

Protective Effects of Carbonated Chitosan Montmorillonite on Vomitoxin-Induced Intestinal Inflammation.

Exposure to vomitoxin (DON) can negatively impact the intestinal health of livestock and poultry, leading to compromised nutrient absorption and utilization, resulting in slowed growth and reduced production efficiency. In this study, we synthesized carbonated chitosan montmorillonite intercalation complexes (CCM) through solution precipitation. The successful formation of intercalation complexes was confirmed by examining functional groups and surface features using infrared spectroscopy and scanning electron microscopy. To assess the impact of CCM on DON-infected mice, we established an experimental mouse model of jejunal inflammation induced by DON infection. We analyzed the effects of CCM on blood biochemical and conventional indices, jejunal inflammatory factors, pathological changes, and the expression of proteins in the MAPK pathways in DON-infected mice. Our results indicate that CCM effectively mitigates the adverse effects of DON on growth performance, jejunal injury, and the inflammatory response in mice. CCM supplementation alleviated the negative effects of DON infection on growth performance and reduced intestinal inflammation in mice. Moreover, CCM supplementation successfully inhibited the activation of the mitogen-activated protein kinase (MAPK) signaling pathway induced by DON. These findings suggest that the mitigating effect of CCM on DON-induced inflammatory injury in the murine jejunum is closely linked to the regulation of the MAPK signaling pathway.

Inorganic–Organic Framework Constructed by the Intercalation of a Double-Decker Porphyrin Metal Complex into Clay Nanosheets and Its Efficient Dye Adsorption Ability

Inorganic–Organic Framework Constructed by the Intercalation of a Double-Decker Porphyrin Metal Complex into Clay Nanosheets and Its Efficient Dye Adsorption Ability

Intercalation of pyrazolone-based oxalamide metal complexes into Na-montmorillonite for catalytic liquid-phase oxidation of phenol using H2O2.

The intercalation of pyrazolone-based oxalamide metal complexes into Na-montmorillonite (Na-MMT) for catalytic liquid-phase oxidation of phenol using H2O2 was undertaken by a flexible ligand method using metal ions including Mn(II), Zn(II), and Sn(II). First, the metal ions were exchanged with the sodium ions of Na-MMT, and then these metal ions were complexed with a new pyrazolone-based oxalamide ligand. The intercalated metal complexes were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, elemental analysis, and thermogravimetric analysis. Phenol was successfully oxidized by heterogeneous catalysts based on Mn(II), Zn(II), and Sn(II) pyrazolone-based oxalamide complexes intercalated into Na-MMT. These heterogeneous catalysts catalyze the liquid-phase oxidation of phenol using H2O2 to catechol as the major product and hydroquinone and benzoquinone as the minor products. The Mn(II) and Zn(II) complexes intercalated into Na-MMT showed better activity than the Sn(II) complex intercalated into Na-MMT and the reaction without the catalyst. It has been shown that some metal ion complexes intercalated into Na-MMT are active catalysts for liquid-phase oxidation of phenol with hydrogen peroxide.

Sensitive photoelectrochemical detection of Hg2+ with low background noise

Herein, a sensitive photoelectrochemical (PEC) biosensor with low background noise for the detection of the potential heavy metal pollutant mercury ion (Hg2+) was developed based on the Nb.BtsI-assisted Hg2+ cycle strategy as the signal amplification channel and the methylene blue (MB)-double stranded DNA (dsDNA) intercalation complex as the PEC signal indicator. When a trace of target Hg2+ was present, a multitude of output DNA (S2) were released from the preformed reaction platform Au@Fe3O4-H1 through the process of Nb.BtsI-assisted Hg2+ cycling, which greatly amplified the input signal of Hg2+ and thus significantly improved the detection sensitivity of this PEC biosensor. The released S2 could be captured by the 1-hexanethiol (HT)/S1/gold nanoparticles (Au NPs)-engineered biosensing interface to generate steady dsDNA (S1/S2) for embedding numerous photoactive substance MB by π-π stacking, giving rise to the formation of the MB-dsDNA intercalation complex. As a unique PEC signal indicator, the MB-dsDNA intercalation complex could produce significant PEC signals for quantitative determination of Hg2+ from 100 fM to 100 nM. Notably, the introduction of photoelectric signal indicator made the PEC biosensor embrace low background noise and negligible false positive signal, thereby producing the highly enhanced of sensitivity and accuracy. With the assistant of the Nb.BtsI-assisted Hg2+ cycle strategy and the MB-dsDNA intercalation complex, the developed biosensor possessed high sensitivity and excellent accuracy for Hg2+ with a low detection limit of 33.3 fM, demonstrating that the proposed sensing platform was provided with a great application prospect in the field of monitoring and control of environmental pollution concerning Hg2+.

Equilibria in the aqueous system of cobalt(II) based on 2-picolinehydroxamic acid and N-(2-hydroxybenzyl)phenylalanine and its ability to inhibit the propagation of cancer cells

Mixed-ligand complexes of cobalt(II) with two bioligands, viz. 2-picolinehydroxamic acid and the reduced Schiff base N-(2-hydroxybenzyl)phenylalanine, were studied in aqueous solution by potentiometry and UV–Vis spectroscopic analysis. The coordination mode of the complexes and their stability were determined and compared to their parent species. Stacking interactions between the rings present in the ligands influence the stability of the complexes. Also, UV–Vis spectroscopy revealed that the stacking interactions affected the intercalation of DNA and mixed-ligand complexes. The in vitro anticancer activity of the free ligand 2-picolinehydroxamic acid and the complexes was tested against cervical and gastric human adenocarcinoma epithelial cell lines. At concentrations of 0.06 and 0.11 mM, the mixed-ligand structures showed the ability to reduce gastric cancer cells with no inhibitory effect on mouse fibroblasts. The cytotoxic effect was accompanied by damage to the cell nuclei, which may confirm that the complexes demonstrate effective binding to DNA. No determination of minimal inhibitory and bactericidal/fungicidal concentrations against the test organisms was possible at higher complex concentrations due to precipitation.

Investigation of methane adsorption in kaolinite–methanol intercalation complex interlayer by Monte Carlo simulations

The methane adsorption at room temperature in the interlayer of the kaolinite–methanol complex (Kln–Me) with different methanol content is investigated with grand canonical Monte Carlo (GCMC) simulation. The mechanism and structure of methanol intercalated kaolinite (Kln) is proposed, and the effect of methanol on methane adsorption by Kln–Me is discussed. The results indicate that the methanol adsorption in the Kln interlayer is mostly physical with non-bonded energy. The interlayer spacing ( d) of Kln–Me optimized by the DREIDING force field is in good agreement with the experimental data measured with X-ray diffraction. The configuration, adsorption properties, and adsorption isotherms are obtained for eight Kln–Me systems with different number (2–20) of methanol molecules in interlayer space. By comparing methane adsorption in the Kln–Me interlayer with different number of methanol molecules, we discover the complex interplay of factors influencing methane adsorption in the Kln–Me interlayer, especially the number of methanol molecules and free volume. It is found that the adsorption capacity of Kln can be enhanced by inserting methanol molecules into its interlayer. This analysis also underscores the GCMC simulation as a viable tool to calculate kaolinite/organic intercalation composites for potential applications.

Synthesis and Investigation of the Properties of Biphasic Hybrid Composites Based on Bentonite, Copper Hexacyanoferrate, Acrylamide and Acrylic Acid Hydrogel.

This article presents a study of the synthesis and characterization of new biphasic hybrid composite materials consisting of intercalated complexes (ICC) of natural mineral bentonite with copper hexaferrocyanide (phase I), which are incorporated into the bulk of the polymer matrix (phase II). It has been established that the sequential modification of bentonite with copper hexaferrocyanide and introduction of acrylamide and acrylic acid cross-linked copolymers into its volume by means of in situ polymerization promote the formation of a heterogeneous porous structure in the resulting hybrid material. The sorption abilities of prepared hybrid composite toward radionuclides of liquid radioactive waste (LRW) have been studied, and the mechanism for binding radionuclide metal ions with the components of the hybrid composition have been described.

NHC-heterocycle carbene gold catalyst intercalated in Layered Double Hydroxides as reusable hybrid catalyst in acidic medium

NHC-heterocyclic carbene metal complexes are efficient catalysts used for the oxidation, amination, cycloaddition or hydration of alkynes. Immobilization of such complex is a strategy to avoid its decomposition/deactivation and allow its recycling. One limitation of the immobilization of carbene metal complexes is the acidic pH required to perform the catalysis of hydration of alkynes. The support used must be resistant in such conditions. Layered Double Hydroxides (LDH) is a widely used material as catalyst support due to their tunable chemical composition and flexible open structure. However, the LDH phases usually found as catalyst support in the literature are chemically instable under severe conditions. In particular, when operating in extreme acidic pH. This study describes the development of a pH-resistant support by screening of LDH with various composition and formulation in order to obtain a stable material at pH down to 3.0, conditions required for a model reaction, the hydration of propargyl alcohol. Then, the intercalation of a NHC-heterocyclic carbene gold anionic complex (NHC-Au) was optimized and fully characterized. The newly heterogeneous catalysts were evaluated for the targeted hydration catalysis reaction. The selected support, a LiAl2 phase obtained by urea method and dried at 80 °C, allowed to immobilized up to 75% of the gold complex. The intercalated catalyst was finally used for the hydration of several alkynes with yields between 84% and 100% and was recycled up to 12 cycles without any activity loss.

Regulation and characterisation of the expansion structure of dickite layers

A dickite with an expanded layer structure was prepared by the co-calcination of the dickite-urea intercalation complex, urea, and potassium chlorate at 450°C. The expansion degree of the dickite layer could be regulated by the mass ratio (P/I) of potassium chlorate to the intercalation complex. XRD and SEM results showed that with the increase of the P/I ratio, the (002) diffraction intensity of expanded dickite gradually weakened and the degree of layer expansion gradually increased. When the P/I ratio exceeded 0.375, the expanded dickite exhibited an accordion-like porous morphology. The layer expansion of dickite exposed more internal layer surfaces, which was conducive to increasing the specific surface area, mesopore volume, and absolute ζ-potential, thus enhancing the adsorption capacity of methylene blue.

Modeling of Magnesium Intercalation into Chevrel Phase Mo6S8: Report on Improved Cell Design

AbstractA good understanding of the limiting processes in rechargeable magnesium batteries is key to develop novel high‐capacity/high‐voltage cathode materials. Thereby, the performance of magnesium‐ion batteries can strongly depend on the morphology of the intercalation cathode. Moreover, high mass loadings are essential for commercialization. In this work the influence of different mass loadings are studied in addition to the impact of the particle size distribution of the active material. Therefore, a detailed continuum model is developed, which is able to describe the complex intercalation of magnesium into a Chevrel phase (CP) cathode. The model considers the thermodynamics, kinetics and interplay of the two energetically different intercalation sites of Mo6S8, which results from its unique crystal structure, as well as the impact of the desolvation on the electrochemical reactions and possible ion agglomeration. Ideal combinations of mass loading and electrolyte concentration as well as the desired CP particle size are determined for the state‐of‐the‐art magnesium tetrakis(hexafluoroisopropyloxy)borate Mg[B(hfip)4]2 electrolyte.

Novel 3,9-Disubstituted Acridines with Strong Inhibition Activity against Topoisomerase I: Synthesis, Biological Evaluation and Molecular Docking Study.

A series of novel 3,9-disubstituted acridines were synthesized and their biological potential was investigated. The synthetic plan consists of eight reaction steps, which produce the final products, derivatives 17a-17j, in a moderate yield. The principles of cheminformatics and computational chemistry were applied in order to study the relationship between the physicochemical properties of the 3,9-disubstituted acridines and their biological activity at a cellular and molecular level. The selected 3,9-disubstituted acridine derivatives were studied in the presence of DNA using spectroscopic (UV-Vis, circular dichroism, and thermal denaturation) and electrophoretic (nuclease activity, relaxation and unwinding assays for topoisomerase I and decatenation assay for topoisomerase IIα) methods. Binding constants (2.81-9.03 × 104 M-1) were calculated for the derivatives from the results of the absorption titration spectra. The derivatives were found to have caused the inhibition of both topoisomerase I and topoisomerase IIα. Molecular docking simulations suggested a different way in which the acridines 17a-17j can interact with topoisomerase I versus topoisomerase IIα. A strong correlation between the lipophilicity of the derivatives and their ability to stabilize the intercalation complex was identified for all of the studied agents. Acridines 17a-17j were also subjected to in vitro screening conducted by the Developmental Therapeutic Program of the National Cancer Institute (NCI) against a panel of 60 cancer cell lines. The strongest biological activity was displayed by aniline acridine 17a (MCF7-GI50 18.6 nM) and N,N-dimethylaniline acridine 17b (SR-GI50 38.0 nM). The relationship between the cytostatic activity of the most active substances (derivatives 17a, 17b, and 17e-17h) and their values of KB, LogP, ΔS°, and δ was also investigated. Due to the fact that a significant correlation was only found in the case of charge density, δ, it is possible to assume that the cytostatic effect might be dependent upon the structural specificity of the acridine derivatives.

Thermodynamics and kinetics of Pb intercalation under graphene on SiC(0001)

SiC-supported graphene intercalated by a two-dimensional Pb monolayer can provide an appealing platform for spintronic applications. Such a monolayer structure is thermodynamically ultrastable, as observed in recent experiments. However, important fundamentals such as the structure of intercalated phases, locations of intercalated atoms, thermodynamic preference for intercalation, and intercalation pathways for this system have not yet been understood conclusively. In this work, extensive density functional theory calculations are performed to assess Pb intercalation thermodynamics and kinetics under graphene on SiC(0001). We find that intercalation of isolated Pb atoms is strongly disfavored over adsorption on top of graphene. However, intercalation of complete Pb layers in the gallery between SiC and graphene buffer layer is strongly favored over supported Pb monolayers and moderately favored over formation of supported large three-dimensional Pb islands. We also find that initiation of intercalation either by individual Pb atoms directly penetrating graphene or by hopping under a static graphene step edge is energetically prohibitive at experimental temperatures. Consequently, more complex intercalation pathways are operative and further analyzed. We demonstrated that once an intercalated Pb monolayer forms around a graphene step edge, a facile Pb mass transport by Pb vacancy-mediated diffusion can be triggered for continued growth of the intercalated monolayer.

Study on the adsorption performance of La(III) and Y(III) on malic acid-kaolinite nanocomposite

• • Malic acid-kaolinite nanocomposite was obtained by intercalation-expansion method. • • Malic acid was inserted into the kaolinite layers and generated gas to expand kaolinite. • • The adsorption capacities of La(III) and Y(III) were as high as 128.5 mg/g and 145.2 mg/g respectively. • • Pseudo-second-order kinetics and Langmuir model fitted the adsorption kinetics and isotherm well. This paper reported an innovative method for the preparation of kaolinite nanocomposites and the application in the adsorption of rare earth metals (REEs). This method firstly inserted malic acid into the kaolinite layers, then the malic acid-kaolinite intercalation complex was calcined with Na 2 CO 3 and malic acid at a high temperature. The power provided by the neutralization reaction promoted malic acid between the kaolinite layers to decompose thermally, and finally obtained the malic acid-kaolinite nanocomposite (EKMA). This method overcame the problem of kaolinite with low adsorption efficiency, which was owing to strong hydrogen bonding between kaolinite layers. The specific surface area of EKMA was significantly increased, and the adsorption capacity for La(III) and Y(III) were as high as 128.5 mg/g and 145.2 mg/g respectively. The pseudo-second-order model and Langmuir model fitted the adsorption kinetics and isotherm well. Therefore, EKMA was expected to be applied in the treatment of REEs waste in industrial wastewater.

An effective model for sodium insertion in hard carbons.

Sodium ion batteries (NIBs) are a potential alternative to Lithium ion batteries (LIBs) because of their lower cost and greater availability. As anodes, hard carbons (HCs) seem to be the most promising candidates for NIBs. Previous numerical theoretical research studies have focussed on the general conditions for Na insertion in HCs, while experiments have shown that the properties of Na insertion in HCs depend strongly on specific material properties of HCs. Our target is building an effective model based on experimental data and the volume expansion phenomenon as a base for constructing chemical potentials and free energies efficiently as the starting point for continuum modeling of intercalation in HCs. In our effective model, HC is treated implicitly, while Na is simulated in a confined space, created by the HC. To reproduce the complex intercalation behavior of Na, different intercalation sites at different energy levels must be introduced. The results show good agreement with the experimental data and clarify the contribution of different Na insertion sites and the exchange between different sites of Na to the open circuit voltage as well as their contribution to the reversible and irreversible capacity of Na in HCs.

Characterization of kaolinite-3-aminopropyltriethoxysilane intercalation complexes

Earlier experimental findings of the kaolinite modified with 3-aminopropyltriethoxysilane (APTES) raised the question of the existence of more stable structures at different reaction temperatures, which has not been fully cleared up yet. Experimental and molecular simulation analyses were used to study different types of kaolinite-APTES intercalation complexes, characterizing their real structures. The displacement reactions of the kaolinite-dimethyl sulfoxide and kaolinite-urea pre-intercalation complexes were applied to synthesize the kaolinite-APTES complexes using the traditional solution/stirring method and the modern solvothermal method. The effects of the type of pre-intercalated molecules, synthesis methods, and reaction temperature (130–230 °C) on the formation of kaolinite-APTES complexes was primarily examined by X-ray diffraction (XRD), and the obtained complexes were characterized by thermal analysis, infrared spectroscopy and transmission electron microscopy. The solvothermal and solution/stirring treatments mainly produced kaolinite-APTES complexes with around 1.0-nm basal spacing. The solution/stirring treatment of the kaolinite-dimethyl sulfoxide pre-intercalation complex at 220 °C proved advantageous to form kaolinite-APTES complexes with around 1.7-nm basal spacing. In molecular dynamics simulations, these complexes with monodentate, bidentate, and tridentate APTES fixations were studied and the distributions and orientations of the grafted and free APTES molecules were predicted.

Pressure on Triethylenediamine–TaS2 Intercalation Complex: Effects on Charge Density Wave Modulation and Molecular Structure

Pressure on Triethylenediamine–TaS₂ Intercalation Complex: Effects on Charge Density Wave Modulation and Molecular Structure