Different Types Of Anions Research Articles

Determination of stability constants of Cu(II)2-bistren cascade complexes by cellmetry method

Cu(II)2-bistren cascade complexes were studied by cellmetry methodology where by choosing appropriate cell sizes of the box the logK values can be calculated by a plane wave DFT method. Different types of anions were chosen to study the effect of the size, shape, and bite length of the donor atoms on the stability constants. It was found that the ligand strain needs to be taken into account to calculate reasonable logK values. Correction factors were determined regarding the energy of the anions and the length of the bistren ligands which resulted in accurate calculated stability constants for all types of anions.

Caged anions in bistren cryptands: Determination of the stability constants by cellmetry method

Bistren host ligands can form stable complexes with different types of anions due to their wide range of structural properties capable of constructing a preferred cavity for the guest anion. Employing a newly developed method, (highly) accurate logK values can be calculated. A standard cell size set was used for most of the complexes; however, based on the energy of the host ligands and the type of the guest anions, some trends and correlations were found to determine the relevant cell sizes of some host ligands. The cell size of the complexes and the anions were always the same. Some unanswered questions in previous experimental studies could also be addressed by the results regarding the highly protonated (LH77+) bistren ligands. For larger complexes, a strategy was developed to calculate accurate stability constants. Based on these results, complexes formed by glyphosate were also studied, and their logK values were predicted.

Effect of interlayer anions on the catalytic activity of Mg-Al layered double hydroxides for furfural and acetone aldol condensation reaction

The aldol condensation reaction between furfural (F) and acetone (A), which typically produces 4-(2-Furyl)-3-buten-2-one (FA), is a critical reaction due to the application of the final product as a flavoring agent in various food items. Traditionally, this reaction is catalyzed by liquid-based catalysts. However, homogeneous liquid-base catalysis often leads to environmental damage. Solid-base catalysis is highly desirable to address the environmental issue due to liquid-base catalysis as it reduces the need for excessive solvents and reagents, thus preserving the environment. In this study, a series of Mg-Al hydrotalcites (HT) intercalated with nitrate ion (HT-NO3), carbonate ion (HT-CO3), or acetate ion (HT-CH3COO) were prepared using three different coprecipitation procedures. Upon calcination at 450 °C, the solids were transformed into mixed metal oxides. Among the calcined hydrotalcites, the catalysts with acetate anion (cHT-CH3COO) or carbonate anion (cHT-CO3) exhibited the highest basicity and thus showed superior catalytic activity for the aldol condensation reaction. Optimal conversion and selectivity were achieved at 90 °C for 2 h using the most basic catalysts (cHT-CO3 and cHT-CH3COO). These catalysts yielded over 98 % conversion with FA selectivity of 76 % for cHT-CO3 and 65 % for cHT-CH3COO, respectively. Notably, the catalyst cHT-CH3COO exhibited higher selectivity towards F2A (32 %) than the cHT-CO3 catalyst (18 %). The effect of interlayer anions on the structural properties of the Mg-Al hydrotalcites was analyzed using X-ray diffraction. Fourier-transform infrared spectroscopy (FT-IR) was employed to investigate the interactions corresponding to different types of anions. The specific surface area and pore volume of the calcined Mg-Al hydrotalcites were determined using nitrogen adsorption (BET), while their total basicity was evaluated through acid-base titration. The reaction kinetics were monitored using gas chromatography.

Assessment of the Antibacterial Potential of Layered Double Hydroxides

Microbes play a crucial role in our lives, and certain pathogenic bacteria are responsible for a wide range of infectious illnesses, food safety, and environmental damage. Layered double hydroxide (LDH), a type of natural two-dimensional substance with a distinctive layered structure also known as anionic clays, has been established as a material that may be utilized to battle a variety of bacterial infections. The interesting properties of LDH include their ease of synthesis, unique structure, uniform distribution of different metal cations in the brucite layer, surface hydroxyl groups, flexible tunability, intercalated anions with interlayer spaces, swelling properties, oxo-bridged linkage, and high chemical and thermal stability, ability to intercalate different types of anions (inorganic, organic, biomolecules, and even genes), delivery of intercalated anions. In the field of biomaterials, LDH has gained prominence as a significant class of layered materials with promising applications. Here, emphasis has been placed on factors such as biocompatibility, anion exchange with the target ion, holding of guest species in the interlayer space, and controlled anion release in a given medium. By utilizing LDH's inherent biocompatibility, several studies have improved its antibacterial characteristics, enabling researchers to add active substances into its matrix for the treatment of bacterial-caused disease. Despite the fact that LDH's antibacterial capabilities have been the subject of several studies, there are currently very few reviews of such findings. Therefore, this study reviewed current developments in new LDH techniques to enhance their antimicrobial activity and provided background on their structures.

Exploring the Nature of Anion-π Interactions: Complexes of π-Acceptors with Fluoro- or Oxoanions Compared to the Associations with Halides.

The variations in the nature and properties of the anion-π complexes with different types of anions are identified via experimental (UV-vis and X-ray crystallographic) measurements and computational analysis of the associations of tetracyanopyrazine, tetrafluoro-, or dichlorodicyano-p-benzoquinone. Co-crystals of these π-acceptors with the salts of fluoro- and oxoanions (PF6-, BF4-, CF3SO3-, or ClO4-) comprised anion-π bonded alternating chains or 1:2 complexes showing interatomic contacts of up to 15% shorter than the van der Waals separations. DFT computations confirmed that binding energies between the neutral π-acceptors and polyatomic noncoordinating oxo- and fluoroanions are comparable to those in the previously reported anion-π complexes with more nucleophilic halides. Yet, while the latter show distinct charge-transfer bands in the UV-vis range, the absorption spectra of the solutions containing oxo- and fluoroanions and the π-acceptors were close to those of the individual reactants. The natural bond orbital (NBO) analysis revealed a very small charge transfer of Δq = 0.01-0.02 e in the complexes with oxo- or fluoroanions as compared to the Δq = 0.05-0.22 e found for analogous complexes with halides. These distinctions were related to the smaller frontier orbital energy gap and better overlap in the complexes with halides (since the highest occupied orbitals of these monoatomic anions are closer in energy to the lowest unoccupied orbitals of the π-acceptors) as compared to that in the multicenter-bonded associations with polyatomic oxo- and fluoroanions. In accordance with these data, the energy decomposition analysis showed that while the complexes of neutral π-acceptors with the fluoro- and oxoanions are formed predominantly via electrostatic interaction, the associations with halides comprised significant orbital (charge-transfer) interactions and they explain their spectral and structural features.

Method and apparatus for automatic high-throughput synthesis of energetic salts

Energetic materials can instantly combust and release a large amount of energy in responding external impulses. Due to its energy characteristics, it has a wide range of practical applications: military and civilian. Designing high-energy-density materials with better performance, lower sensitivity, and more environmental friendliness has become a hotspot in the field of energetic materials in recent years. Energetic salts are formed by acid-base or metathesis reactions of different types of anions and cations. Energetic salts are a new class of energetic materials which were developed in recent years. Usually, they have high nitrogen content, high enthalpy of formation, high detonation performance, are relative stable to external stimuli, and have a wide range of application prospects in the fields of new explosives: low characteristic signal propellants, gas generators, low smoke or smokeless pyrotechnics. The synthesis method of energetic salts is simple, and the types of energetic materials are greatly enriched. This research takes energetic salts as the synthesis target and adopts multi-channel automation technology for high-throughput synthesis, which can improve the efficiency, reduce labor costs, and greatly increase the synthesis speed, which is of great significance for accelerating the synthesis of new energetic salts.

Leaf-like ionic covalent organic framework for the highly efficient and selective removal of non-steroidal anti-inflammatory drugs: Adsorption performance and mechanism insights

In recent years, ionic covalent organic frameworks (iCOFs) have become popular for the removal of contaminants from water. Herein, we employed 2-hydroxybenzene-1,3,5-tricarbaldehyde (TFP) and 1,3-diaminoguanidine monohydrochloride (DgCl) to develop a novel leaf-like iCOF (TFP-DgCl) for the highly efficient and selective removal of non-steroidal anti-inflammatory drugs (NSAIDs). The uniformly distributed adsorption sites, suitable pore sizes, and functional groups (hydroxyl groups, guanidinium groups, and aromatic groups) of the TFP-DgCl endowed it with powerful and selective adsorption capacities for NSAIDs. Remarkably, the optimal leaf-like TFP-DgCl demonstrated an excellent maximum adsorption capacity (1100.08 mg/g) for diclofenac sodium (DCF), to the best of our knowledge, the largest adsorption capacity ever achieved for DCF. Further testing under varying environmental conditions such as pH, different types of anions, and multi-component systems confirmed the practical suitability of the TFP-DgCl. Moreover, the prepared TFP-DgCl exhibited exceptional reusability and stability through six adsorption–desorption cycles. Finally, the adsorption mechanisms of NSAIDs on leaf-like TFP-DgCl were confirmed as electrostatic interactions, hydrogen bonding, and π-π interactions. This work significantly supplements to our understanding of iCOFs and provides new insights into the removal of NSAIDs from wastewater.

Layered double hydroxides: an insight into the role of hydrotalcite-type anionic clays in energy and environmental applications with current progress and recent prospects

Layered double hydroxides are also known as hydrotalcite-like compounds that have emerged as fascinating mineral materials with numerous applications in catalysis, adsorbents, plastic, agriculture, and electronics. These are promising materials that gained significant interest due to their captivated properties, such as ease of preparation, ability to intercalate different types of anions, high thermal stability, high biocompatibility, and easy biodegradation. Moreover, the attractive characteristics including tailored/tuneable acidity and basicity, basal spacing, memory effect, anion exchange capability, and surface area of these minerals have led to increased focus with their application horizons extended to diverse areas of science and technology. The current review sheds light on various rational design strategies related to their production, features, and applications in energy and environment. The review mainly highlights the synthetic design and/or fabrication with other hybrids and their use in broad-spectrum green chemistry and environmental sustainability applications including their use as a catalyst for photoreduction of CO2, biomass conversion into chemicals/fuels, energy-storage system components, corrosion scavenging additives in concrete materials and waste treatments.

Ba2F2][Ge2O3S2]: An Unprecedented Heteroanionic Infrared Nonlinear Optical Material Containing Three Typical Anions

Metal chalcogenides, oxides, and halides are the three most typical materials classes for mid-infrared nonlinear optical (mid-IR NLO) crystals that can expand the spectral ranges of solid-state lasers to the mid-IR region. However, it is difficult for each of them to satisfy all the property requirements of mid-IR NLO crystals owing to their own defects. On the contrary, combining multiple anionic units as much as possible to construct heteroanionic compounds is an effective strategy for the design of new high-performance IR NLO crystals. Although in recent research, a series of heteroanionic materials containing two types of anions (i.e., chalcogenides-halides, oxychalcogenides, and oxyhalides) have been reported, the compounds that contain all three types of anions have still been unexplored. Herein, we report the first IR NLO crystal [Ba2F2][Ge2O3S2], which contains all three typical anions (O2–, S2–, and F–) and satisfies the key property requirements as a promising IR NLO candidate, including a strong SHG response (∼1.4× AgGaS2), a large band gap (Eg = 4.45 eV), and wide IR transmission (0.24–9.0 μm). This research indicates that coupling different types of anions in one compound is a more attractive strategy to explore new IR NLO materials with excellent properties.

Imidazolium-Modified Bispyrene-Based Fluorescent Aggregates for Discrimination of Multiple Anions in Aqueous Solution.

A great number of anions exist in biological systems and natural environment, and are highly relevant to human health and environment quality. It is necessary to develop simple and effective sensors to differentiate and identify those similar or different anions. Here, an imidazolium-modified bispyrene-based fluorescent amphiphilic probe DPyDIM was synthesized and its aggregates were applied to detect and discriminate various anions. The fluorescent aggregates exhibit ratiometric responses to different types of anions. Moreover, the ratiometric responses to different types of anions are featured with multiple-wavelength cross-reactivity. The collection of fluorescence variation at four typical wavelengths can generate distinct recognition patterns to specific anions. The heat map and principal component analysis results verify that this single fluorescent sensor system can effectively and sensitively identify 16 kinds of anions that belong to phosphorus-containing, sulfur-containing anions, and anionic surfactants. The cross-reactive sensing of the amphiphilic fluorescent aggregates was attributed to the different influences on the aggregation behaviors of the probes by different anions. The present work provides a promising strategy for effective detection and discrimination of multiple anions by employing dynamic fluorescent aggregates as a sensing platform.

Multifaceted potential applicability of hydrotalcite-type anionic clays from green chemistry to environmental sustainability

Hydrotalcite-like anionic clays (HTs) also known as Layered double hydroxides (LDHs) have been developed as multifunctional materials in numerous applications related to catalysis, adsorption, and ion-exchange processes. These materials constitute an important class of ionic lamellar solid clays of Brucite-like structure which comprise of consecutive layers of divalent and trivalent metal cations with charge balancing anions and water molecules in interlayer space. These materials have received increasing attention in research due to their interesting properties namely layered structure, ease of preparation, flexible tunability, ability to intercalate different types of anions, electronic properties, high thermal stability, high biocompatibility, and easy biodegradation. Moreover, HTs/LDHs have unique tailorable and tuneable characteristics such as both acidic and basic sites, anion exchange capability, surface area, basal spacing, memory effect, and also exhibit high exchange capacities, which makes them versatile materials for a wide range of applications and extended their horizons to diverse areas of science and technology. This study enlightens the various rational researches related to the synthetic methods and features focusing on synthesis and/or fabrication with other hybrids and their applications. The diverse applications (namely catalyst, adsorbent to toxic chemicals, agrochemicals management, non-toxic flame retardants, and recycling of plastics) of these multifunctional materials related to a clean and sustainable environment were also summarized.

IMPURITY LUMINESCENCE CENTERS IN FLUORAPATITE FROM QUARTZ-BEARING PARAGENESIS ACCORDING TO PHOTO-, CATHODE- AND SYNCHROTRON-INDUCED LUMINESCENCE

Apatite is typically characterized by a wide variety of spectrum and kinetic characteristics of luminescence; luminescent images of grains are often zonal. A variety of conditions for the formation of the mineral in various types of associations and in many types of host rocks contributes to the occurrence of impurities of various luminogen ions in its structure. The variety of luminescence is associated with impurities of d-metals, REE, different types of anions, as well as with the effects of co-activation in various combinations. The paper presents the results of a comparative study of photo-, cathode- and synchrotron luminescence of apatite (by the example of samples from crystal-bearing deposits of the Neroi region, Subpolar Urals). Using a Jeol JSM6390LV SEM equipped with a Horiba H-CLUE iHR500 attachment, cathodoluminescence spectra of apatite were obtained in the 200–800 nm range. The spectra and kinetic characteristics of apatite luminescence upon excitation by synchrotron radiation at 10 and 300 K have been analyzed for the first time; the physical nature of the excitation bands of the three main luminescence centers Ce3+, Eu2+ and Mn2+ has been examined; it is shown that the luminescence excitation with the energy transfer can be carried out in processes initially initiated by interband transitions or photoionization. The data obtained are important for expanding the possibilities of mineral cathodoluminescence with spatial and spectral resolution and its use in applied problems.

Complex coordinated functional groups: A great genes for nonlinear optical materials

Complex coordinated functional groups [MAxBy] (M = Central coordination element; A, B = P, O, S, Se, F, Cl, Br or I) are composed of different types of anions A, B jointly linked to the same central cation M, which are in high potential to tune the physical properties of materials, e.g., second-order susceptibility, energy gaps and birefringence. Recently, Compound containing complex coordinated functional groups have attracted great attention in the nonlinear optical (NLO) field and a large number of this type crystals exhibit promising NLO performance. However, the inherent relationship between ionic group structure and optical properties of complex coordinated NLO materials have not been systematically studied. This article systematically summarizes complex coordinated NLO materials in recent five years from the perspective of the internal relationship between crystal structure and optical properties. In addition, we propose the ideal combination and arrangement modes for structural building units, and also reveal the influence of complex coordinated functional groups [MAxBy] toward the NLO response, optical band gap and phase matching ability of complex coordinated NLO materials.

Mechanisms of ion transport in lithium salt‐doped polymeric ionic liquid electrolytes at higher salt concentrations

AbstractWe used atomistic simulations to study the mechanisms of ion transport in salt‐doped polymeric ionic liquid systems at higher salt concentrations. Consistent with the experimental observations, our simulations indicate that at higher salt concentrations, the anion mobilities become lower than that of the lithium cations. Further, the anion mobilities become relatively insensitive to the salt concentration, while the mobilities of lithium increase with increasing salt concentration. We rationalize the results for the anion mobilities by considering the fractions of anions which are exclusively coordinated with the polycations (Type1); co‐coordinated with cations and lithium (Type2); and those exclusively coordinated with lithium (Type3). By considering the coordination characteristics of the different types of anions and their hopping motions, we demonstrate that the net anion mobilities results from a compensation effect of the salt concentration dependence of the mobilities of the different anions. With respect to the mobilities of the lithium ions, we demonstrate that the latter moves primarily by a structural diffusion mechanism involving refreshing of the solvation shell during hopping. Further, for the majority of the lithium ions, the solvation shell is shown to be comprised of co‐coordinated Type2 anions, and that the number of polycations and the unique polymer chains involved in such coordination decreases with increasing salt concentration. Such changes are shown to weaken the solvation shell around the lithium, thereby facilitating faster ion motion. Together, our results suggest that systems in which the anion which exhibits a stronger coordination to the polycation in comparison to that of the lithium can facilitate higher transference numbers without a concomitant reduction in the mechanical strength.

Influence of Anions on the Electrolyte/Electrode Interfacial Dynamics Probed By in-Situ/Operando Soft X-Ray Absorption Spectroscopy

Since the demonstration of room temperature plating and stripping of calcium with high capacities and low polarization using Ca(BH4)2 as the electrolyte, there is considerable interest in the study of electrochemical processes in calcium batteries in addition to the conventional magnesium batteries. The greater polarizability of Ca2+ over Mg2+represents greater configurational flexibility, facilitating ionic cluster formation and rapid delivery of Ca2+ ions to the electrode interface. With such motivation in calcium batteries, a critical question to address is the probing of the solvation and charge transfer mechanism at the electrode/electrolyte interface. In this work, the solvation and charge transfer mechanisms of two calcium electrolytes, Ca(BH4)2 and calcium hexafluoroisopropoxyborate (Ca(BHFIP)2), with different types of anions, are compared under operando conditions. It has been reported that when BH4 - is substituted by the more weakly coordinated BHFIP-, the electrolyte ionic conductivity will increase by an order of magnitude, which demonstrates the strong coordination of BH4 - to Ca2+ in THF. To probe the Ca2+ coordination chemistry difference at this electrolyte/electrode interface as a function of the type of anions, total electron yield (TEY) mode soft X-ray absorption spectra (XAS) sensitive to the interfacial speciation have been employed under operando electrochemical conditions. It was observed that the Ca(BHFIP)2 in THF shows a small shoulder on the right side of the L2-edge and a pre-edge peak on the left side of the L2-edge peak. A less prominent pre-edge peak is also observed on the left side of the L3-edge peak. These signatures become more prominent when the potential is swept negatively and are not reversible when the potential is swept positively in a cyclic voltammetry cycle. On the other hand, the Ca(BH4)2 in THF is more reversible, and no shoulder peak on the right side of the L2-edge peak was observed. The TEY spectra indicate their differences in the Ca2+coordination chemistry at the electrode/electrolyte interface as a result of the interacted anions and it will guide future development of electrolytes for calcium batteries. The detailed solvation structure of the calcium is to be resolved with the DFT calculations. Such operando soft XAS studies of the interfacial dynamics reveal the transient processes in the solvation at the electrolyte/electrode interface and will pave the way for the development of calcium electrolytes in batteries.

Supramolecular Salts of Germanium (IV) with Tartaric Acid, Zinc and 1,10‐Phenanthroline/2,2‘‐Bipyridine: Synthesis, Structural Features and Selective Recognition

AbstractThe study describes synthesis methods, structural features and thermal stability of the novel cation‐anionic coordination compounds, crystallized in Sohnke chiral space group P21 [Zn(phen)3]2[Ge2(OH)(HTart)(μ‐Tart)2] ⋅ 23H2O (1) and [Zn(bipy)3][Ge2(OH)2(μ‐Tart)2] ⋅ 5H2O (2). Dependently on the second heterocyclic ligand (1,10‐phenanthroline ‐ phen (1) or 2,2’‐bipyridine ‐bipy (2)) complex zinc cations showed their ability to recognize selectively two different types of anions: dimeric [Ge2(OH)2(μ‐Tart)2]2− (2) and more complex [Ge2(OH)(HTart)(μ‐Tart)2]4− (1) with additional terminal tartaric acid ligand (HTart3−) and different coordination polyhedrons of Ge in its structure. Compounds 1 and 2 were characterized by X‐Ray, IR, MS and thermogravimetric analyzes. Analysis of intermolecular interactions using Hirshfeld surface‐based tools indicated the dominant role of various hydrogen intermolecular interactions such as H…H, H…O for both compounds, and C…C (π⋅⋅⋅π) for 1.

Ionization of ionic liquids under laser desorption/ionization

Despite various studies of ILs as MALDI matrices, however, so far no relationship has been foundbetween the composition of ILs and their ability to serve as «good» matrices. For a preliminary experiment,in order to evaluate the characteristics of ILs before being used as a matrix in MALDI-MS, it is necessary tostudy the mass spectral behavior for the matrices themselves under LDI conditions. Therefore, the purpose of this work was to analyse ion liquids based on the cation imidazolium in combination with different types ofanions by the LDI method. Ionic liquids were synthesized in the Laboratory of catalytic processes for thesynthesis of organoelement compounds of G.K. Boreskov Institute of catalysis SB RAS (Novosibirsk). Itshould be noted that this ionic liquid was first synthesized in this Laboratory. Analyses were performed usinga Bruker UltraFlex II time of-flight mass spectrometer. Eleven ion liquids based on substituted cation imidazolium in combination with different types of anions were analysed by method laser desorption/ionization in the paper. In all mass spectra of ionic liquids obtained in the positive ion mode, cation produced a major peak and its fragmented ions. Homologous series characterized by the loss of the methyl group have been recorded. According to the more stable carbon-carbon or nitrogen bond in the heterocyclic system than in the carbon-carbon bond in the aliphatic, ion peaks are observed in the mass spectra, characteristic of the loss of methyl fragments from the aliphatic chain. In the LDI spectra obtained in the negative ion mode, the signals of the anions of ionic liquids and their fragments were observed. The combined use of the spectra obtained in positive and negative mode makes it possible to increase the reliability of identification. This makes it possible to use the revealed patterns of fragmentation for the structural analysis of ionic liquids. The analyzed ILs can be used as MALDI matrices, because they do not form dimers, assassinates, are characterized by the absence of adducts with metal ions, which is important for their further use as matrices. BMIMC6F5BF3 was first described by the LDI-MS method. It was shown that the observed fragmentation of the molecular ion of this IL is typical for most ILs with similar cations.

Fluorimetric detection of distinct lyotropic anion interactions on nanoscopic surfaces

The molecular structure, stability and function of proteins, nucleic acids, and many other colloidal entities including nanomaterials depend greatly on their highly specific response towards surrounding solvent molecules and inorganic ions. In order to earn an unambiguous mechanistic insight into the origin of these effects, water-soluble fluorescent carbon nanomaterials having amide groups in a hydrophobic microenvironment were successfully employed as the model colloidal system in this research study. Quantum dots with acidic functionalities were first of all prepared using a simple carbon precursor. Subsequently, chemical modification of carbon quantum dots (CQDs) was carried out with isopropylamine to impart protein-like amide richness to the nanoparticle surface. Moreover, the prepared CQDs were found to be highly fluorescent. Fluorescence intensity, interestingly, showed unique modulation patterns on incubation with different types of anions. Lipophilic chaotropic anions such as I−, SCN−, and Br− showed concentration-dependent fluorescence quenching whereas hydrophilic kosmotropic anions like SO42− had almost no impact on the nanomaterial fluorescence. This striking observation in the case of chaotropic anions can be correlated to their strong partitioning affinity for the amide groups on the nanomaterial surface. High charge density anions like sulphate, on the other hand, are mostly excluded from the colloidal interfaces. The current study emphasizes the fact that the functional groups available on the surface of macromolecules as well as anion's inherent thermodynamic parameters in a solvent play a pivotal role in the observed anion specificity.

Beyond Size Complementary Factors in Anion-Tetralactam Macrocycle Complexes: From Intrinsic Gas-Phase to Solvent-Predicted Stabilities.

The gas-phase affinities of different types of anions X– (halogen anions, oxoanions, and hydrogenated anions) toward a model tetralactam-based macrocycle receptor (1), defined in terms of stability of an anion–receptor complex (1 + X–) against its disintegration, were evaluated by dissociation studies using a mass spectrometry-based methodology and supported by theoretical calculations (density functional theory–PBE0). The gas-phase complex with Cl– was found to be tailor-made for the macrocycle 1, while 1 + SA– (SA– = salicylate anion) and 1 + HSO4– were the weakest ones. Other complexes displayed a relatively low-stability dispersion (<1.2 kcal·mol–1). The 1/εr approach of the electrostatic contribution scaling method was used to predict the stability trends in a dimethyl sulfoxide solvent from the gas-phase binding energy partition using the symmetry-adapted perturbation theory. High deformation energy and differences in solvation energies were suggested to be the main sources of inconsistency in the predicted and experimental stabilities of 1 + F– and 1 + H2PO4– complexes.

Studies on the Drug Loading and Release Profiles of Degradable Chitosan-Based Multilayer Films for Anticancer Treatment.

This study demonstrates the possibility of developing a rapidly degradable chitosan-based multilayer film for controlled drug release. The chitosan (CHI)-based multilayer nanofilms were prepared with three different types of anions, hyaluronic acid (HA), alginic acid (ALG) and tannic acid (TA). Taking advantage of the Layer-by-Layer (LBL) assembly, each multilayer film has different morphology, porosity and thickness depending on their ionic density, molecular structure and the polymer functionality of the building blocks. We loaded drug models such as doxorubicin hydrochloride (DOX), fluorescein isothiocyanate (FITC) and ovalbumin (Ova) into multilayer films and analyzed the drug loading and release profiles in phosphate-buffered saline (PBS) buffer with the same osmolarity and temperature as the human body. Despite the rapid degradation of the multilayer film in a high pH and salt solution, the drug release profile can be controlled by increasing the functional group density, which results in interaction with the drug. In particular, the abundant carboxylate groups in the CHI/HA film increased the loading amount of DOX and decreased rapid drug release. The TA interaction with DOX via electrostatic interaction, hydrogen bonding and hydrophobic interaction showed a sustained drug release profile. These results serve as principles for fabricating a tailored multilayer film for drug delivery application.