Journal of Inclusion Phenomena and Macrocyclic Chemistry最新文献

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.

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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.

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Heterogeneous photocatalysis caused by solar energy is a promising green strategy for the treatment of organic wastewater contaminants. However, many conventional photocatalysts have limited applications owing to defects such as inability to absorb visible light, fast charge recombination, and poor adsorption capacity. Herein, a new photocatalyst, Q[6]-PTA, was obtained via the supramolecular self-assembly of cucurbit[6]uril (Q[6]) and phosphotungstic acid (PTA) in solution. Structural characterization demonstrates that Q[6] and PTA have their original structures in Q[6]-PTA, and the driving force of their self-assembly is the electrostatic interaction between the positive outer surface of Q[6] and PTA anion. Compared with PTA, Q[6]-PTA has a larger specific surface area and porosity, increased number of active sites, enhanced adsorption properties, and considerably higher photoresponse range (from ultraviolet to visible light), moreover, it can effectively inhibit the charge recombination of PTA. In visible light, Q6-PTA was used as a photocatalyst to degrade methyl orange (MO) in the aqueous solution with a degradation rate of > 99%. Its excellent photocatalytic performance can be attributed to the higher specific surface area and reduction in band gap and reduction in photogenerated electron and hole recombination rate. After repeated use for three times, the Q[6]-PTA catalyst demonstrated high activity for degrading MO. This study demonstrates that the supramolecular self-assembly of cucurbit[n]uril/heteropolyacid is a facile and effective strategy for developing efficient and stable heterogeneous photocatalysts.

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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.

We use a highly water-soluble acyclic cucurbit[n]uril ACB-01 that bears eight carboxylate groups. ACB-01 has excellent solubility in water and high affinity to the cyanine dyes pseudoisocyanine (PIC) and pinacyanol (PIN) to afford 1:1 complexes. The complexation has been studied by UV–vis absorption, fluorescence and nuclear magnetic resonance (NMR) spectroscopy, and the binding constants (K_a) are determined to be (1.54 ± 0.15) × 10⁶ M⁻¹ and (6.09 ± 0.82) × 10⁵ M⁻¹, respectively. This complexation leads to the inhibition of the J-aggregation of PIC and H-aggregation of PIN. However, competitive guests methyl viologen and 1-adamantanamine hydrochloride can recover their respective J- and H-aggregation due to more stable complexation occurs between them and ACB-01. Thus, we have established a new method of reversibly controlling dye aggregation by regulating the concentration of ACB-01 and competitive guests.

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Porphyrins, owing to their unique physicochemical properties, hold great potential as candidates for the synthesis of new materials and active pharmaceutical drugs. The introduction of functional groups into porphyrin structures enables the creation of novel compounds with finely tuned structural and optical properties, as well as complex-forming abilities. In this study, spectral and thermochemical investigations were conducted to explore the complex formation of 5-[4′-(N-methyl-1″,3″-benzoimidazol-2″-yl)phenyl]-10,15,20-tris-(N-methyl-3′-pyridyl)porphyrin triiodide with synthetic (poly[d(GC)2], poly[d(AT)2]) and natural (ssDNA, ctDNA) nucleic acids. It was observed that the porphyrin forms complexes with poly[d(AT)2] and ssDNA, localized within the major groove of the biopolymer. Additionally, the porphyrin forms multiple intercalation complexes with varying geometries when interacting with poly[d(GC)2] and ctDNA. These findings demonstrate a new potential for enhancing the selective binding of ligands with nucleic acids (NA). Moreover, the study highlights the methodological aspect that establishing the type of formed complexes based on ligands’ electronic absorption spectra, known as “fingerprints,“ may lead to incorrect conclusions.

A novel [c2] daisy chain was successfully constructed by the hermaphroditic monomer of dibenzo[24]-crown-8 (DB24C8) derivative bearing secondary ammonium salt (1) from the analysis of the solution-phase behavior of parent monomers and single-crystal X-ray analysis. ¹H NMR spectroscopy was employed to show that the crown ether moiety and the secondary ammonium salt unit underwent acid–base and alkali metal cation dependent switches. The complexation behavior of this hermaphroditic monomer in the solution was further demonstrated to exhibit the controlled photophysical behavior as a reversible luminescent switch in the presence of acids or bases. Solid morphology was determined by SEM.

In this study, we designed and prepared two new β-cyclodextrins (1 and 2) bearing ethylene glycol chains to develop highly water-soluble cyclodextrins. They had excellent water solubility and could successfully dissolve 17-β-estradiol in water, which was considered a poorly soluble drug model. Additionally, the nuclear magnetic resonance structural analysis of a mixed sample of 17-β-estradiol and 1 in D₂O–H₂O suggested two different types of inclusion complexes with different 17-β-estradiol molecule orientations inside the cavity of 1.

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Macroscopic supramolecular self-assembly (MSSA) has emerged as a new area of research in the field of supramolecular chemistry. The construction of macroscopic supramolecular structures using interfacial assembly by modifying functional groups on the surface of macromolecules and exploiting the weak interactions between surface functional groups is gaining more and more attention. With the advancement of gel technology, significant progress has been made in MSSA. However, MSSA still faces challenges such as low detection efficiency and accuracy. In this paper, a MSSA detection technique based on HALCON machine vision is designed. The technique first locates the hydrogel block (HB) by shape-based template matching and then uses machine vision techniques to detect whether the HBs are assembled. Finally, through the self-assembly judgment and detection of 500 groups of HBs, the results show that the technology can efficiently and accurately complete the MSSA detection function, which is of great significance for the development of supramolecular chemistry.