Formation Of Inclusion Compounds Research Articles

2,3-per-acylated α and β cyclodextrins as inducers of helical liquid crystalline phases

ABSTRACT For the first time, a comprehensive study of the mesomorphic, physical and orientation properties of helical mesophases induced by partially acylated cyclodextrins was carried out. Using polarisation microscopy, the formation of a helical mesophase was established when a nematic mixture of polar 4-alkoxy-4’-cyanobiphenyls (CB-2) was doped with chiral 2,3-per-acetylated and 2,3-per-propionylated α- and β-cyclodextrins. The clearance temperatures and helical pitch were measured. The high efficiency of helix twisting under the influence of these dopants and an increase in the orientational order parameter of the liquid crystal matrix were ascertained. Using Haller’s extrapolation method for approximation the temperature dependences of birefringence a decrease in inverse helix pitch (1/p) upon heating was shown to be due to a reduction in the LC order parameter. Quantum chemical simulation of the acetylated α- and β-cyclodextrins structure and their solvates with 4-pentyloxy-4’-cyanobiphenyl was performed, and their interaction energies and dipole moments were calculated. The formation of inclusion compounds of LC molecules into the internal cavity of acylated CDs was established. The higher interaction energy and helical twisting power, as well as the least destabilisation of the mesophase were shown to be observed for β-cyclodextrin derivatives.

Optimization of ultrasonic-assisted debittering of Ganoderma lucidum using response surface methodology, characterization, and evaluation of antioxidant activity.

Ganoderma lucidum (G. lucidum) has gained increasing attention as a potential health care product and food source. However, the bitter taste of G. lucidum has limited its development and utilization for the food industry. The response surface methodology was employed to optimize the inclusion conditions for the debittering of G. lucidum. The effects of 2-hydroxypropyl-β-cyclodextrin concentration (12-14 g/mL), ultrasound temperature (20-40°C and host-guest ratio (1:1-2:1) on response variables were studied. The physical characteristics of inclusion complexes prepared through spray drying and freeze drying were analyzed. The antioxidant activity of the different treated samples was subsequently investigated. Study results showed that, in comparison to the control group, the inclusion solution displayed a significantly enhanced taste profile under optimal processing conditions, exhibiting an 80.74% reduction in bitterness value. Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (NMR) studies indicated the successful formation of inclusion compounds. The moisture content and bulk density of spray-dried powder were found to be significantly superior to those of freeze-dried powder (p<0.05). In comparison to the diluted solution, the inclusion liquid demonstrated a 20.27%, 30.01% and 36.55% increase in ferric ion reducing antioxidant power (FRAP), hydroxyl radical scavenging and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging respectively. Further, the DPPH clearance of microencapsulated powder was not significantly different from that of tocopherol at a concentration of 25 mg/mL. In summary, the study provides theoretical basis and methodological guidance to eliminate the bitterness of G. lucidum, and therefore provide potential options to the use of G. lucidum as a food source.

Armoring the cathode with starch gel enables Shuttle-Free Zinc-Iodine batteries

Zinc-iodine batteries (ZIBs) have been recognized as a promising energy storage device due to their high energy density, low cost and environmental friendliness. However, the development of ZIBs is hindered by the shuttle effect of polyiodides which results in capacity degradation and poor cycling performance. Inspired by the ability of starch to form inclusion compounds with iodine, we propose to use a starch gel on the cathode to suppress the shuttle of polyiodides. Herein, porous carbon is utilized as a host for iodine species and provides an excellent conductive network, while starch gel is used as another host to suppress polyiodides shuttle, resulting in improved battery performance. The test results demonstrate that the conversion between I−/I2/I3− in the cathode and the effective inclusion role of starch suppress the shuttle of polyiodides during the charging process. Meanwhile, based on the electrochemical tests and theoretical DFT calculations, it is found that starch has a stronger ability to adsorb polyiodides compared to carbon materials, which enables effective confinement of polyiodides. The ZIBs used the cathode with starch gel exhibit high coulombic efficiency (>95 % at 0.2 A/g) and low self-discharge (86.8 % after resting for 24 h). This strategy is characterized by its simplicity, low cost and high applicability, making it significant for the advancement of high-performance ZIBs.

ИССЛЕДОВАНИЕ МЕТОДОМ ФУНКЦИОНАЛА ПЛОТНОСТИ ОБРАЗОВАНИЯ СОЕДИНЕНИЯ ВКЛЮЧЕНИЯ И АДДУКТА НА ОСНОВЕ КВЕРЦЕТИНА И КУКУРБИТ[7]УРИЛА

In this work, the structures of an inclusion compound and an adduct based on quercetin and cucurbit[7]uril are obtained using the density functional theory with the PBE functional and the Alrich Def2-TZVP atomic basis set for all atoms. The aim of the work was to find out whether it is possible to use CB[7] as a molecular "container" for the antioxidant quercetin for targeted delivery to a given area of the body, organ or cell. It is shown that fully gas-phase calculations, calculations in the molecular model and in a more rigorous combined molecular-continuum model give significantly different quantitative results for the thermodynamic characteristics of the processes of adduct and inclusion compound formation. At the same time, the results obtained in the combined model convincingly demonstrate the thermodynamic possibility of forming these structures in an aqueous solution. The formation of supramolecular compounds occurs due to the formation of many weak bonds, among which dispersion interactions can play a significant role. Therefore, at the last stage of calculations, dispersion interactions were taken into account within the framework of the semi-empirical Grimme D4 model. Such calculations showed that taking into account dispersion interactions in the considered systems has little effect on ΔGo298 of adduct formation, while for the inclusion compound its thermodynamic probability of formation becomes more noticeable.

Investigation of the hydrogen bonded host‧‧‧guest and guest‧‧‧guest interactions present in complexes of a polyaromatic wheel-and-axle host compound with dioxane, morpholine, piperidine and pyridine

1,4-Bis(diphenylhydroxymethyl)benzene (H), a host compound possessing wheel-and-axle geometry, was found to possess host ability for dioxane (DIO), morpholine (MOR) and piperidine (PIP), forming inclusion compounds with each one with 1:2 host:guest ratios. This observation prompted an investigation of the host behaviour in mixtures of these guest compounds but where pyridine (PYR) was also considered (PYR was reported earlier to also form a 1:2 complex with H). In mixtures, H demonstrated significant affinities for, more especially, MOR and PIP, while DIO and PYR were usually disfavoured guest species. Single crystal X-ray diffraction experiments revealed that MOR (a favoured guest species) interacted by means of three hydrogen bonds with both adjacent guest and host molecules, plausibly explaining the host preference for this guest species; each of DIO, PYR and PIP were involved in only one interaction of this type with H. Total energy calculations revealed that the host-guest molecular pairs involving preferred MOR and PIP possessed significantly lower energies than those with disfavoured DIO and PYR. Thermal analyses demonstrated that the complex containing the least favoured guest compound, H‧2(DIO), possessed the lowest thermal stability of the four complexes, but these experiments did not clearly explain the affinity of H for MOR.

Improvement in the stability and bioavailability of pumpkin lutein using β-cyclodextrin microcapsules.

Growing concerns about food nutrition and food supplies have encouraged the development of effective constituents. Lutein is an important nutrient element, and its health benefits are gradually being recognized. Lutein, as a carotenoid antioxidant, can protect cells and organs from damage caused by free radicals. However, in processing, storage, and usage, lutein is unstable and often undergoes isomerization and oxidative decomposition, which limits its wide range of applications. β-Cyclodextrin is an ideal substrate to prepare microcapsule structures, which are highly biocompatible and nontoxic. During the lutein encapsulation process, ideal β-cyclodextrin microcapsules were used to form inclusion compounds. The results reveal that the encapsulation efficiency of the microcapsules reached 53%. Moreover, using ultrasonic-assisted extraction can easily and efficiently purify lutein. In addition, the capability of the β-cyclodextrin composite shell can enhance the bioactive molecules' activity and stability.

Recent progress in encapsulation and controlled release of pesticides based on cyclodextrin derivative carriers

In the context of the continuous increase in global grain production, accompanied by a large amount of investment in various pesticides, herbicides, fungicides, and other chemical pesticides. It has caused inevitable environmental problems and food safety problems. Current research suggests that the use of cyclodextrins and their derivatives to protect pesticides can significantly reduce the number of agrochemicals that pollute the environment. Using the cavity properties of cyclodextrins, we can refer to the similar way in which drug molecules make cyclodextrins and cyclodextrin polymers to form inclusion compounds. Overall, β-cyclodextrin and its derivatives are used as a new pesticide excipient to improve the stability of pesticides, prevent their oxidation and decomposition, improve the solubility and bioavailability of pesticides, reduce the toxic side effects of drugs, and mask the odour of drugs. In this review, we focus on summarising the recent research progress of β-cyclodextrins and their derivatives in pesticides and other fields, and provide a systematic classification of β-cyclodextrin polymers, as well as new synthesis methods and techniques in various applications. Finally, the future development of cyclodextrin-like polymers is foreseen, and issues arising from the research are discussed and addressed in depth.

Synthesis of linear and cyclic organic sulfonic acid-modified Cu-Al layered double hydroxides and their adsorption properties

Over the past few years, many substances have been investigated for their potential application as adsorbent materials. The combination of a layered double hydroxide (LDH) and CH/π interactions enables selective adsorption through the differences in the electron density of the aromatic ring. Thus, in this study, two organic anions, namely the linear 1-octane sulfonate (OS-) and cyclic sulfonated-β-cyclodextrin (SCD13-), were intercalated into the interlayers of a Cu-Al LDH by coprecipitation (Cu/Al ratio, 3.0; chemical ratio, 2.0). The SCD13- anion was selected because β-cyclodextrin comprises hydrophobic cavities that allow the formation of inclusion compounds. X-ray diffraction (XRD), total organic carbon (TOC) analysis, and inductively coupled plasma-atomic emission spectrometry (ICP-AES) revealed that the as-synthesized OS-Cu-Al LDH and SCD-Cu-Al LDH were both oriented perpendicular to the LDH layer. Subsequent absorption experiments with m-aminophenol (AP) and m-nitrophenol (NP), which have similar structures but different aromatic ring electron densities, confirmed a Freundlich-type adsorption mechanism and revealed that adsorption occurred on a non-uniform surface for both LDHs. The results also revealed excellent NP and AP adsorptions for the linear OS•Cu-Al LDH and cyclic SCD•Cu-Al LDH, respectively. This was attributed to the strong hydrophobic interactions in the former and strong CH/π interactions in the latter. This study shows the potential of using linear and cyclic organic sulfonic acid-modified LDHs for the selective recovery of the desired aromatic organic compounds.

Recent Advances in the Synthesis and Applications of Nitrogen-Containing Macrocycles.

Macrocyclic nitrogen-containing compounds are versatile molecules. Supramolecular, noncovalent interactions of these macrocycles with guest molecules enables them to act as catalysts, fluorescent sensors, chiral or nonchiral selectors, or receptors of small molecules. In the solid state, they often display a propensity to form inclusion compounds. All of these properties are usually closely connected with the presence of nitrogen atoms in the macrocyclic ring. As most of the reviews published so far on macrocycles were written from the viewpoint of functional groups, synthetic methods, or the structure, search methods for literature reports in terms of the physicochemical properties of these compounds may be unobvious. In this minireview, the emphasis was put on the synthesis and applications of nitrogen-containing macrocyclic compounds, as they differ from their acyclic analogs, and at the same time are the driving force for further research.

Inclusion of CO2, NH3, SO2, Cl2 and H2S in porous N4O4-donor macrocyclic Schiff base

The removal and detection of highly toxic and environmentally harmful gases such as SO2, H2S and CO2 is a hot topic of the scientific community. Porous organic compounds, in particular, imine-based macrocycles, are promising materials for this purpose. In this paper we have used porous N4O4-donor macrocyclic Schiff base (1,6,20,25-tetraaza-2,5:8,9:17,18:21,24:27,28:36,37-hexabenzo-10,16,29,35-tetraoxa-cyclooctatriakonta-1,6,20,25-tetraen) (1) for sorption of NH3, SO2, Cl2, CO2 and H2S. Five novel inclusion compounds 1xNH3, 1xSO2, 1xCl2, 1xCO2 and 1xH2S were prepared by a single-crystal to single-crystal (SC-SC) transformation. Single-crystal X-ray diffraction (SCXRD) analysis of 1xCO2 and 1xNH3 inclusion compounds have shown that CO2 molecule resides in the plane of the macrocyclic ring connected by weak C–O … π interactions to the host, and no host-guest interactions in 1xNH3 were observed. The relative thermal stabilities of the host-guest systems (Ton – Tb parameter) is in the range from 93 (1xNH3) to 132 °C (1xH2S), indicating the formation of stable inclusion compounds. Although used gases are highly reactive and corrosive, FT-IR and powder diffraction studies indicate that the molecular and crystal structure of the host is constant upon gas sorption. The activated compound displays moderate uptake (0.35 mmol/g) of CO2 at 298 K. The relatively high thermal stability, constant molecular and crystal structure of inclusion compounds with interesting optical properties (determined by solid state UV–Vis) make this material potentially useful for the detection of toxic gases.

Cyclodextrin-Modified Nanomaterials for Drug Delivery: Classification and Advances in Controlled Release and Bioavailability.

In drug delivery, one widely used way of overcoming the biopharmaceutical problems present in several active pharmaceutical ingredients, such as poor aqueous solubility, early instability, and low bioavailability, is the formation of inclusion compounds with cyclodextrins (CD). In recent years, the use of CD derivatives in combination with nanomaterials has shown to be a promising strategy for formulating new, optimized systems. The goals of this review are to give in-depth knowledge and critical appraisal of the main CD-modified or CD-based nanomaterials for drug delivery, such as lipid-based nanocarriers, natural and synthetic polymeric nanocarriers, nanosponges, graphene derivatives, mesoporous silica nanoparticles, plasmonic and magnetic nanoparticles, quantum dots and other miscellaneous systems such as nanovalves, metal-organic frameworks, Janus nanoparticles, and nanofibers. Special attention is given to nanosystems that achieve controlled drug release and increase their bioavailability during in vivo studies.

Deformations of cyclodextrins and their influence to form inclusion compounds

AbstractDeformations of the three most common cyclodextrins (,, and) were induced to form inclusion compounds with sertraline and abacavir. The deformations were obtained from classical molecular dynamics (CMD) using as starting point X‐ray structures. The molecular dynamics were performed in two ways, over the cyclodextrins with and without the presence of a guest. Two characteristic rings within these cyclodextrins were used to measure the distortions observed along with the molecular dynamics. A docking approach was used to build inclusion compounds over the structures obtained from CMD without the presence of sertraline or abacavir. Thus, we compared structures of inclusion compounds obtained from deformations induced by the presence of a guest or with intrinsic deformations exhibited by each cyclodextrin. After this step, each structure was optimized by the PBE0‐D3/6‐31G(d,p) method, and the electron density delivered by this method was used to perform the quantum theory of atoms in molecules approach to analyze intermolecular contacts between sertraline, or abacavir, and three cyclodextrins. From this procedure, we found that inclusion compounds obtained from X‐ray structures present the highest energies over the potential energy surface. Thus, for getting low‐lying energy structures of inclusion compounds, deformations on cyclodextrins are necessary.

Enclathration by a Halogenated Host: Structures, Polymorphism, Kinetics, and Guest Exchange

The host tetrakis(p-bromophenyl)ethylene forms inclusion compounds with 1,4-dioxane (chiral and racemic polymorph pair), cyclohexanone, dimethyl sulfoxide, and 3-pentanone. Their structures have be...

1H NMR spectroscopic characterization of inclusion complex of desferrioxamine B chelator and β-cyclodextrin

In this work the complexation between desferioxamine B (DFOB), and β-Cyclodextrin (β-CD) in solution was investigated using 1H NMR spectroscopy. Inclusion compound formation was confirmed by the upfield shifts of H3 and H5 protons, located inside the cavity of β-CD, and downfield shifts of some of the methylene protons of DFOB, observed during NMR titration experiments. Using the continuous variation method, we determined a 1:1 stoichiometry and the association constant was calculated using a nonlinear least-square regression analysis implemented in CONSTEQ, a software developed in our group. A theoretical molecular docking study was additionally performed to ascertain possible conformations of the inclusion complex.

Inclusion Complex of Sea Buckthorn Fruit Oil with β‐Cyclodextrin: Preparation Characterization and Antioxidant Activity

AbstractThis study aims to produce an inclusion complex between β‐cyclodextrin (β‐CD) and sea buckthorn fruit oil (SBFO) by using the saturated aqueous solution method and then to compare the resultant solution with the crude mixtures. In this study, the SBFO is extracted by Soxhlet extraction, which is optimized through the single‐factor test. The main constituent of the SBFO is identified by gas chromatography‐mass spectrometry (GC‐MS), which confirms eight fatty acids. Fourier transform infrared spectroscopy, thermogravimetric analysis‐differential scanning calorimetry, optical microscopy, scanning electron microscopy, and the result‐characterized synthesized compounds confirm the formation of stable inclusion compounds by the SBFO with β‐CD. The yield values of the inclusion complex and the SBFO loading content are 64.87 ± 2.26% and 9.2 ± 1.58%, respectively. Comparing the crude fruit oil, β‐CD–SBFO, and saponified fruit oil reveals differences in their 2,2‐diphenyl‐1‐pycrylhydrazyl and 2,2′‐azinobis‐(3‐ethylbenzthiazoline‐6‐sulfonate) antioxidant activities. These findings suggest that the SBFO inclusion complex after β‐cyclodextrin is stabilized and is a good antioxidant. This solution improves the inadequacy of the water solution and the instability of the SBFO. This study also implies that β‐CD is a cost‐effective and straightforward carrier for extending the applications of SBFO as a food or medicinal additive.Practical applications: In this experiment, the SBFO is converted from oil to powder to increase its efficacy as an additive to health and food products.

Detailed Structural Examination, Quantum Mechanical Studies of the Aromatic Compound Solarimfetol and Formation of Inclusion Compound with Cucurbituril

This manuscript aims to look at the structure and the other physical and chemical properties of solriamfetol, which is used to treat excessive sleepiness, using electronic structure methods. Density functional theory optimizes the ground state geometries of the molecules, and the frontier molecular orbitals are analyzed using B3LYP functional and 6-311++G (2d,p) basis sets. They give ample information regarding the electronic properties and descriptors, which can be used to predict the same molecule's biological activity. Evaluation of aromaticity has been performed using the nuclear induced chemical shift (NICS) measurements. Electrostatic potential, average local ionization energy and the assessment of non-covalent interactions in the molecule show effects biological activity potential. The sound interaction between the drug molecule with cucurbit[8]uril strongly advocates its possibility be used as a drug delivery system.

A superhydrophilic and high demulsification aramid nanofibers membrane with novel poly-pseudorotaxane structure for oil-in-water separation

Oily wastewater caused by the traditional oil spills and the increment of emerging lipid (such as biodiesel) pollution endangers human and nature seriously. Herein, we conceive a novel β-cyclodextrin-threated interface demulsification structural strategy to assemble superhydrophilic aramid nanofibers (ANFs) membranes for surfactant-stabilized oil-in-water emulsion separation. Aim to modify the monomers, p-Phenylenediamine (PPD) molecules were covered by β-cyclodextrin (β-CD) to form inclusion compounds. Different poly (p-phthaloyl-p-phenylenediamine) with poly-pseudorotaxane structure (β-CD@PPTA) was obtained by low-temperature solution polycondensation by adjusting the proportion of modified monomers. The corresponding β-CD@ANFs membrane was successfully fabricated by non-solvent induced phase separation. The effect of β-CD@PPD monomers on the structure, element content, surface wettability, separation performances and durability of the modified membrane were investigated systematically. The modified membranes had the superhydrophilicity and underwater superoleophobicity characteristics. The flux and oil rejection of membrane both raised with the increased added proportion of β-CD@PPD monomers. The well-designed membrane exhibited tween 60 stabilized N-hexadecane-in-water emulsion permeances over 126.59 ± 5.35 L/m2h with separation efficiency above 99.73%. More significantly, the membrane had long-term demulsification performance and ideal purification effect on the separation of biodiesel wastewater, showing forceful prospect in removing lipid oil pollutants from the oil-in-water emulsions. The membrane prepared by poly-pseudorotaxane modification could better serve the development of oil-in-water separation field.

Physical–chemical and antimicrobial activity of sulfadiazine sodium salt with β-cyclodextrin supramolecular systems

Cyclodextrins (CDs) have been used over the past years as a promising pharmaceutical excipient in order to improve drug bioavailability by supramolecular interaction between host and guest molecules. Herein, β-cyclodextrin (βCD) and its derivatives, 2-hydroxypropyl-β-cyclodextrin (HPβCD) and methyl-β-cyclodextrin (MβCD), were used to form inclusion compounds (ICs) with sulfadiazine sodium salt (SDS). The isothermal titration calorimetry and nuclear magnetic resonance experiments confirmed the interaction between the species in solution, which were used to test in vitro against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. The diffusion tests have revealed that the ICs were more efficient against Staphylococcus aureus and Pseudomonas aeruginosa than free SDS molecule. In addition, for Escherichia coli MβCD ICs was more effective than the other ICs and pure SDS. These results demonstrated not only the importance to understand the supramolecular interaction between host and guest molecules, but also the capability to CDs to improve drug molecules activity.

Host-guest molecular encapsulation of cucurbit[7]uril with dillapiole congeners using docking simulation and density functional theory approaches

Binding affinity and intermolecular interactions are essential characteristics that could be used to comprehend molecular recognition between molecules in supramolecular host-guest systems. This work presented a molecular docking simulation and density functional theory (DFT) calculation at the B3LYP-631g(d) level of theory on dillapiole and its derivatives (guest compounds) complexation with cucurbit[7]uril (host compound). The supramolecular host-guest inclusion complex binding energies, − 4.46 to − 5.47 kcal mol−1 and − 0.53 to − 15.38 kcal mol−1 for docking and DFT calculation, respectively, were calculated, and the intermolecular interactions such as the hydrogen bonding, electrostatic, dispersion, and pi-alkyl formation involved were observed. The negative binding energies of D1-CB [7], D2-CB [7], D3-CB [7], D4-CB [7], D5-CB [7], D6-CB [7], and D-CB [7], computed from both the theoretical approaches, suggested the possible inclusion of the guests inside the cucurbit[7]uril cavity, enabling the formation of stable inclusion compounds. However, the significant difference in the binding energy values from the DFT calculation demonstrated a clustered preference in terms of the complex stabilisation, with D2-CB [7], D3-CB [7], D5-CB [7], and D6-CB [7] dominantly favourable, while D1-CB [7], D4-CB [7], and D were inclusion complexes with the least favourable. Encapsulation of the guests’ structural frame as a whole or a part and steric constraint associated with the guests’ substituents positioning in addition to the intermolecular interactions were also noted to induce stabilisation in the binding energy, thus reflecting a preferable inclusion complex. Besides, the theoretical calculations on the rationalisation of the selected guests’ energy barrier were found to correlate well with experimental works of hydroboration oxidation synthesis to produce alcohol derivatives of dillapiole.

Mechanisms of Chiral Transfer in Optically Active Dopant – Nematic Liquid Crystal Systems

Induction of helical mesophases by incorporating chiral dopants into the nematics matrix is the promising modern trends in the chemistry of liquid crystals. This process is associated with a unique phenomenon - an amplification of chirality in liquid-crystalline phases, which ensures the detection of enantiomers by their chiral induction, much more sensitive than other methods. The relevance of this approach is due to the need to create perspective electro-optical devices operating with ultra-low control voltages based on twist effects, chromatographic stationary phases with high chiral selectivity, flexible magnets, photo-sensitive nanostructures, and other smart LC materials. The successful solution of these problems is impossible without experimental research and theoretical comprehension of the mechanisms of third level chiral transfer optically active dopant – nematic liquid crystal. In the last decade, a large number of works have appeared on the solution of these problems. This review is devoted to a generalization of the experimental results and a theoretical description of the transfer of molecular chirality to orientationally ordered systems with the participation of both chiral molecular substituents with an asymmetric carbon atom and planar or quasi-planar fragments chirally distorted relative to each other. The stereochemical aspects of induction associated with the structural correspondences of the dopant and nematic liquid crystal, as well as the main classes of optically active additives, are discussed. Application of metal complexes, both Werner and macroheterocyclic, are presented. Special attention is paid to the results of the mechanisms study of chiral transfer due to various intermolecular interactions: hydrogen bonding, axial coordination, and the formation of inclusion compounds. The high efficiency of induction of spiral mesophases has been demonstrated with a combination of different self-assembly mechanisms in liquid crystal - chiral additive systems.