Journal of Inclusion Phenomena and Macrocyclic Chemistry最新文献

Stabilization of reactive organic species by encapsulation in self-assembly supramolecules is a popular technique. Citral, a common antimicrobial and flavor compound, is highly sensitive to oxidation, especially when exposed to elevated temperature and light. In this study we evaluated the encapsulation efficiency of citral in cyclodextrin-metal organic framework (CDMOF) to prevent oxidation, provide chemical stability, and control the release of citral for various industrial applications including packaging. Computational simulations indicated the formation of stable inclusion complex between CDMOF and citral with binding energy of the IC approximately − 3.89 kcal mol⁻¹. We observed around 11.83% w/w inclusion of citral in CDMOF as measured using TGA. Host–guest interactions between CDMOF and citral were further elucidated using FTIR, DSC, and SEM. Encapsulation of CDMOF in citral offers higher temperature stability, and extended-release kinetics.

Abstract

Inclusion complexes of benzene (Bz) with cyclodextrins (CD) have been investigated so far using non-NMR techniques in various solvents resulting in conflicting data. Here, the first application of NMR spectroscopy in combination with rigorous statistical analysis of the results has allowed us to determine accurately the stoichiometry of complexes and their association constants. Titration measurements have been performed by ¹H NMR spectroscopy in D₂O at a magnetic field B₀ of 14.1 T. αCD and γCD host molecules form weak 1 : 1 complexes with Bz. In contrast, Bz and βCD build 1 : 1 and 2 : 1 complexes coexisting in solution with large binding constants. Binding of second benzene molecule is strongly cooperative.

New coumarin derivatives C1, C2, and C3 with different substituents (methylphenyl, chlorophenyl, and nitrophenyl) were prepared and characterized using various spectroscopic techniques. C1 and C2 display luminescence when excited at 325 nm, while C3 has weak emission at 335 nm. The binding properties of these derivatives toward transition metals and lanthanum cations were studied using UV-visible absorption spectroscopy, and the former cations were found to form ML₂ complexes by titration method. The chelation of each ligand with metal cations induced changes in their luminescence properties.

A hydroxypropyl β-cyclodextrin (HPCD)/5-fluorouracil (5-FU) inclusion complex was loaded into konjac glucomannan hydrogel successfully by co-assembly. The influence of HPCD on the structure and properties of konjac glucomannan (KGM) hydrogel was investigated. The networks of KGM/HPCD hydrogel became flat and firm after HPCD intervened. The KGM/HPCD hydrogel had diversified microstructures including HPCD molecular cavities, porous lamellar structure in fibrous bands. The X-ray diffractometry (XRD) results reflected amorphous characters of the KGM/HPCD xerogel. The analytical data of Fourier transform infrared spectrometry (FT-IR) and differential scanning calorimetry (DSC) confirmed the supramolecular interactions between KGM and HPCD molecules in the gel network were mainly H-bonding interactions. HPCD improved KGM/HPCD hydrogel by crosslinking physically to construct a novel drug delivery system in the presence of sodium carbonate. The KGM/HPCD hydrogel achieved more effective and sustained drug release, in which HPCD cavities shared responsibility for the controlled release of chemotherapeutic 5-FU molecules. Rheological measurements also showed the presence of HPCD increased the elastic modulus (G') of the novel KGM/HPCD hydrogel.

Graphical abstract

Through co-assembly, a green drug delivery system was successfully constructed with hydroxypropyl β-cyclodextrin/5-fluorouracil inclusion complex loaded into konjac glucomannan hydrogel. By dialysis experiments, the drug 5-fluorouracil release rate from the inclusion complex loaded hydrogel was prolongated remarkably compared to that from single 5-fluorouracil loaded hydrogel. For the inclusion complex loaded hydrogel with different 5-fluorouracil concentrations, or under different physiological conditions, the drug cumulative release appeared also evident difference. This green drug delivery system has important potential application in medical engineering material.

As the first generation of macrocyclic hosts, crown ethers have excellent host-guest recognition characteristics and are widely used in molecular recognition, catalysis, drug delivery and other fields. Porous organic polymers (POPs) with adjustable porosity and stable network structure have become advanced materials for molecular storage, heterogeneous catalysis, water purification and energy storage. In recent years, crown ether-based porous organic polymers have attracted extensive attention due to their excellent performance, which combine supramolecular hosts with traditional polymer, and have created a new field for supramolecular chemistry and material science. In this review, we discusses the research status of crown ether-based porous organic polymers in structure and pollutant adsorption, including selective adsorption of metal ions in water and removal of organic pollutants, and prospected the promising applications and future development direction of crown ether-based porous organic polymers.

Two coordination complexes were synthesized using vanadyl(IV) acetylacetonate and H₂denm/H₄dpim in MeOH/CHCl₃ and characterized. The complexes were [VO(denm)(H₂O)]·CH₃OH (1) and [VO(H₂dpim)(CH₃COONa)]·CH₃OH (2) (H₂denm = 2,2′-[[(1R,2R)-1,2-diphenyl-1,2-ethanediyl]bis[(E)-nitrilomethylidyne]]bis[6-methoxyphenol]; H₄dpim = [(2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(6-methoxyphenol)]. The vanadyl(IV) species of 1 and 2 exhibited distorted octahedral geometries with two N and two O atoms of each ligand and aqua/acetate ligand. Complex 1 did not exhibit emissions in the solid and solution states, whereas complex 2 exhibited strong band maxima in the solid state and a dimethyl sulfoxide solution. The magnetic properties and electron paramagnetic resonance spectra of 1 and 2 revealed that they were S = 1/2 spin systems. The antioxidant activity of 2 was higher than those of 1 and ascorbic acid.

The nanoplatform for drugs demonstrates favorable stability and high therapeutical advantages in the bloodstream. Here, by using hydroxyethyl starch (HES) 130/0.4 and serum albumin, which were widely used as volume expanders in intravenous therapy, we synthesized a new HES 130/0.4-loaded bovine serum albumin (BSA) nanoparticles and investigated the binding mechanism in the simulated physiological environment with considerations of compatibility. Analysis of the fluorescence quenching data of BSA by HES using the Stern–Volmer equation proved the formation of a 1:1 ground state complex. The binding parameters (ΔS° = 329 J mol⁻¹ K⁻¹, ΔH° = 6.38 × 10⁵ J mol⁻¹, and ΔG = − 3.04 × 10⁵ J mol⁻¹) at body temperature manifested that the interaction was exothermic and driven by hydrophobic interactions. The binding distance was calculated as 2.73 nm and showed a high possibility of Förster resonance energy transfer. The structural alterations of BSA were assessed both qualitatively and quantitatively through the application of 3D/synchronous fluorescence and circular dichroism techniques, respectively, which showed adaptive changes in secondary structures. The results presented in this study offer not only novel ideas of albumin-based NP synthesis, but precise and comprehensive primary data that elucidate the mechanisms of HES-BSA interaction, helping to comprehend its pharmacodynamics in blood.

This work aims to study the production of hydrogen peroxide gas (H₂O₂) through photocatalysis. It consists of two main parts. In the first part, we explore the optimal conditions for synthesizing H₂O₂ gas from humidity using a gas system photoreactor. Through experimentation, we discovered that the fabricated photoreactor, equipped with three series of coated photocatalyst-supporting plates, can synthesize H₂O₂ gas up to 3 ppmv. The photoreactor incorporates key components, including a photocatalyst material, UV light source, ventilation fan, and air filter. The identified optimal conditions included a relative humidity of 60‒65% RH and an air flow rate of 12.0 m/s. The TiO₂/1%SiO₂ photocatalyst, composed of SiO₂ particles smaller than 63 μm, yielded the most favorable results. The second part focused on studying the role of SiO₂ in TiO₂/SiO₂. We observed that modifying the TiO₂ morphology with SiO₂ created a pore structure on the surface. This structural modification leads to the formation of Ti‒O‒Si bonds, which facilitate electron and hole trapping on the photocatalyst surface. Furthermore, the presence of hydroxyl groups on the surface enhanced the attraction of reactant molecules. XRD results reveal a mixed-phase structure of TiO₂ (anatase‒rutile)/SiO₂ amorphous, contributing to improved electron and hole pathways within the photocatalyst.

Graphical abstract

In an endeavor to ameliorate the solubility and subsequent oral bioavailability of Cefixime (CEF), a drug noted for its deficient water solubility, the formulation of ternary inclusion complexes was executed utilizing hydroxypropyl-β-cyclodextrin (HP-β-CD) and sulfobutylether-β-cyclodextrin (SBE-β-CD), in conjunction with N-methyl-D-glucaminet (MG). This development was realized through the application of a mechanochemistry technique, acknowledged for its “green” credentials. The complexes' physicochemical attributes were meticulously examined through various analytical techniques: Fourier-transform infrared spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC), Powder X-ray Diffractometry (XRD), and Scanning Electron Microscopy (SEM). Notably, the ternary complexes exhibited an uplift in apparent drug solubility, especially when juxtaposed with binary complexes. A prominent augmentation was perceived in the stability constant (Kc) and complexation efficiency (CE) when MG was integrated into the ternary complexes with HP-β-CD or SBE-β-CD. Further exploratory molecular docking and molecular dynamics studies underscored MG’s role in augmenting complex stability by serving as a bridge between CEF and cyclodextrins (CDs). The parallel artificial membrane permeability assay (PAMPA) indicated a conspicuous enhancement of CEF permeability in the ternary complexes relative to the control–free CEF. The particle size and zeta potential of the mechanochemically processed ternary complexes in liquid form were assessed using Dynamic Light Scattering (DLS). Moreover, in vivo evaluations revealed the ternary complexes to manifest notably superior oral bioavailability when compared to unadulterated CEF. Lastly, through the rapid storage assay, a heightened physicochemical stability was observed in the mechanochemically synthesized CEF ternary supramolecular inclusion complexes, compared to the pure drug, intimating a pioneering approach for the oral delivery of CEF, ensuring improved bioavailability.

Graphical abstract

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.