Journal of Inclusion Phenomena and Macrocyclic Chemistry最新文献

Considering that many vitamins can be easily degraded, developing ways to avoid the degradation process and the availability of these vitamins is essential. Thus, this study aims to use layered zinc hydroxysalt (LHS) as a slow-release option that provides thermal stability for administering vitamins. Two compounds were synthesized, LHS/B3-1, which presented basal spacing of 9.63 Å, corresponding to a vitamin monolayer, and LHS/B3-2, which is a mixture of two phases, one with a basal distance of 9.92 Å and a secondary one with a basal distance of 15.43 Å, corresponding to a vitamin monolayer and bilayer, respectively. After intercalation, an increase of 175 °C in the thermal stability of vitamin B3 was observed, occasioned by the interaction with the layers of the matrix. Vitamin B3 was slowly released from LHS/B3-1 and LHS/B3-2, and 68.8% and 56.9% were released in 44 h, respectively. The release of the vitamin from LHS/B3-1 and LHS/B3-2 was divided into three stages. The results suggest that surface diffusion is initially involved in the release of B3 from intercalation products, where the anion dissociates from the surface of LHSs, followed by B3 release controlled by a diffusion process via intra-particle or surface diffusion.

Graphical Abstract

Diamide macrocycles are valuable intermediates for the synthesis of aza crown compounds as well as more complex ligands such as various cryptands and cryptohemispherands. Their versatility in many fields, such as chemistry, biochemistry, biophysics, biology, agriculture, industry, medicine, molecular diagnosis, sensors, and phase transfer catalysts, has captured the interest of many. In the first step, 2,4-dimethylphenol was converted to the oxythiobis [4,6-dimethylphenyl] (1) by reacting with thionyl chloride. Then, oxythiobis [4,6-dimethyl phenoxy methyl acetate] (2) was obtained from the reaction of oxythiobis [4,6-dimethylphenyl] (1) with methyl chloroacetate. The reaction of oxythiobis [4,6-dimethyl phenoxy methyl acetate] (2), with a diethylenetriamine, produced the tri-aza dibenzo sulfoxide macrocyclic diamides (3). Bis [tri-aza dibenzo sulfoxide macrocyclic diamides] (4) was prepared from the reaction of tri-aza dibenzo sulfoxide macrocyclic diamides (3) with a suitable active compound such as diacid or dichloride. The structures of all synthesized compounds were characterized by ¹H NMR, ¹³C NMR, FT-IR, and mass spectra.

Two pairs of diastereomerically pure calix[4]arene phosphoric acid derivatives with ABHH and ABCH substitution patterns were synthesized via phosphorylation and phosphotropic rearrangement on the narrow rim. These new cone-shaped, inherently chiral calixarenes were tested as organocatalysts in the stereoselective aza-Diels–Alder reaction of imines with Danishefsky's diene, as well as in the stereoselective epoxide ring opening.

Pillar[n]arenes are a relatively new family of macrocyclic molecular hosts, consisting of methylene-linked phenol-based monomers attached in a para-substituted configuration. The macrocyclic nature of these molecules provides a well-defined internal cavity, into which smaller guest molecules can be included to form supramolecular host-guest inclusion complexes. The para-oriented attachment yields relatively rigid cylindrical or pillar-like molecular and cavity shapes, hence the name. In addition to the unique shape of these cavities (compared to the related meta-substituted calixarenes, for example), the aromatic nature of the cavity walls also contributes to distinctive host properties of pillar[n]arenes and guest affinities. Neutral pillar[n]arenes, such as those with alkyl substituents, are generally insoluble in water, and thus their host properties are studied in nonaqueous media. This review article will provide a comprehensive summary of the reported host binding studies of pillar[n]arenes in nonaqueous solution. A wide range of specific pillar[n]arenes have been studied in this way, as have a wide variety of sizes and types of guests. The emphasis will be on studies in which the value of the binding association constant K_a was measured and reported, to consider the effect of guest size, shape, and nature and the host size and substituents on the binding ability of pillar[n]arenes. The main objective of the paper is to provide a summary and overview of the host binding abilities of this fascinating family of molecular hosts in nonaqueous solution.

Graphical abstract

Honokiol (HK) is an active compound in the traditional Chinese medicine Magnolia officinalis, which has antibacterial and disease-resistant effects on pathogenic microorganisms. However, due to its poor water solubility, its application is severely limited. In this study, Methyl-β-Cyclodextrin (M-β-CD) was used to encapsulate honokiol to improve its water solubility. The inclusion complex of HK with M-β-CD (HK/M-β-CD IC) were prepared by freeze-drying method, Phase solubility studies indicate that HK with M-β-CD forms inclusion complex in a stoichiometric ratio of 1:1. However, considering that the inclusion process is reversible. In order to obtain inclusion complex with higher encapsulation efficiency, we use response surface optimization to optimize the encapsulation process. The encapsulation efficiency of the obtained inclusion compound is 87.64%.The structure of inclusion complex was characterized by FTIR, TGA, SEM, XRD and NMR. The molecular docking was used to predict the structure of inclusion complex. In addition, compared with free HK, the solubility of the inclusion complex in water was significantly enhanced, about 1228 times that of the free HK. And it enhances the antibacterial activity against Trichoderma koningii.

Porous high surface area supramolecules have been widely researched for controlled delivery and chemical stabilization of active molecular species. Metal–organic frameworks (MOFs), a vast category of high surface area microporous compounds, can be tailored to encapsulate specific active molecules, and control their release kinetics in the headspace of a product-package system for treatment and shelf-life extension of various agricultural produce. Hexanal has been widely reported to reduce post-harvest losses due to its antimicrobial, antifungal, ethylene-modulating, and phospholipase D (PLD) inhibiting characteristics. In this work, we synthesized Calcium-Squarate MOF by a quick simple mechanochemical process using bioderived linkers and non-toxic endogenous cations. We herein report the encapsulation of hexanal in Ca-Squarate MOF, and probe the strength of non-covalent host–guest interactions of hexanal encapsulated in the pores. The synthesized MOF crystals were characterized by thermal analysis, infrared spectroscopy, and diffraction studies. We observed approximately 20% encapsulation of hexanal by weight using thermo-gravimetric analysis. The infrared spectroscopy and simulation study supported the formation of hydrogen bonds between H atoms of hexanal and O atoms of the Ca-Squarate MOF with the strongest binding affinity of  −3.81 kcal mol⁻¹. Crystals maintained their porous structure and microscale morphologies post-encapsulation, as observed using X-ray diffraction and scanning electron microscopy. These results are encouraging for the potential use of hexanal encapsulated MOFs in active packaging applications.

In this investigation, the wheel-and-axle host compound, 1,4-phenylene-bis(di-p-fluorophenylmethanol) (H), was demonstrated to have inclusion ability for each of PYR, 2MP, 3MP and 4MP (1:1, 1:2, 1:2 and 1:2 were the H: G ratios). In the equimolar guest competition experiments, H was observed to have an overwhelming affinity for PYR and 4MP relative to 2MP and 3MP. In fact, selectivity coefficients calculated from the non-equimolar binary guest competition experiments suggested that this host compound would be an efficient candidate for the separation of all PYR/2MP mixtures and a 40:60 4MP/3MP solution through host-guest chemistry strategies. SCXRD analyses established the preferred guests (PYR and 4MP) to be involved in significantly shorter stabilizing classical hydrogen bonding interactions with H, explaining the selectivity behaviour of this host compound in the guest mixtures. Additionally, Hirshfeld surface considerations also explained this behaviour, but only for PYR. Furthermore, thermal analyses were used to ascertain the relative thermal stabilities of the four complexes and, satisfyingly, the PYR- and 4MP-containing complexes possessed the greater thermal stabilities compared with H·2(2MP) and H·2(3MP), as was demonstrated by a comparison of their guest release onset temperatures.

Novel derivatives of diazadioxocalix[2]arene[2]triazine were synthesized and evaluated for their catalytic effects on direct asymmetric Aldol reactions in organic solvents. Chiral groups were attached to the heteroatom-bridged calix[2]triazine scaffold through reactions involving (R)/(S)-1,2,3,4-tetrahydro-1-naphthylamine with diazadioxocalix[2]arene[2]triazine. Diazadioxocalix[2]arene[2]triazine derivatives were found to be effective catalysts for the reaction of acetone with aromatic aldehydes. According to the obtained results, it has been determined that the moiety of the catalyst affects the configuration of the Aldol product. The Aldol adducts were obtained in excellent yields (93%) and enantioselectivities (96%).

Quercetin (QC) has various biological activities such as anti-inflammatory and antibacterial properties. However, due to its poor solubility and stability, the application of QC in clinical practice is limited. Nanosponge (NS), as a new drug carrier, can significantly improve the solubility of low-soluble drug components, and significantly improve the efficacy and bioavailability of drugs. In this paper, cyclodextrin nanosponges (CDNS) were synthesized by cross-linking β-cyclodextrin with diphenyl carbonate (DPC) in a green and safe synthetic pathway. As wall material, CDNS were further used to encapsulate quercetin and quercetin-cyclodextrin nanosponges (QCNS) were formed. The resultant CDNS and QCNS were characterized by scanning electron microscopy, infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. The results showed that CDNS and QCNS were successful prepared. The solubilizing impact of CDNS on quercetin was investigated. The results showed that its solubility in water was 176 times higher than that of pure QC. The cumulative release of quercetin and QCNS over 48 h and the cumulative transdermal penetration over 12 h were measured. The antioxidant and antibacterial properties of QCNS were determined. QCNS exhibited superior stability, permeability, and sustained-release properties compared to pure quercetin, and had notable bacteriostatic and antioxidant capabilities.