Journal of Inclusion Phenomena and Macrocyclic Chemistry最新文献

Inspired by protein assemblies in biological systems, various artificial protein assemblies have been constructed in these decades. Hemoprotein containing porphyrin iron complex, heme, is a unique building block of the artificial protein assemblies due to the structures, physicochemical properties and functions. In the case of hemoprotein containing b-type heme, the heme cofactor is non-covalently bound to the heme-binding site, heme pocket, in the protein matrix. This review summaries our efforts to utilize heme–heme pocket interactions toward supramolecular hemoprotein assembling systems with various structures and/or functions. Simple monomeric hemoprotein, mainly cytochrome b₅₆₂, was employed as a useful building block and synthetic heme was attached to the cysteine-introduced variant to form a building block showing self-assembling behavior by interprotein heme–heme pocket interactions. The modulations of linker between synthetic heme and protein surface and/or protein modification site contribute to provide various structures such as fiber, ring, branched shape and micelles. Furthermore, hexameric hemoprotein was utilized for another building block with supramolecular approach toward light harvesting system by replacement of heme cofactors with porphyrinoid photosensitizers. A series of artificial hemoprotein assembling systems will contribute to new-type of functional biomaterials.

The colorimetric sensing system for glutathione (GSH) was constructed by the mixture of three components, an anionic dye 2-(5-bromo-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)phenol (BrPAPS), a cationic polyelectrolyte poly(diallyldimethylammonium chloride) (PDADMAC), and Cu²⁺ in an aqueous solution. BrPAPS was complexed with Cu²⁺ in a 2:1 molar ratio via the electrostatic interaction with PDADMAC (BrPAPS₂-Cu²⁺-PDADMAC). The addition of GSH to the complex caused a hypsochromic shift with a distinct colorimetric response from red to yellow since the regeneration of the original BrPAPS through the interaction between GSH and Cu²⁺ in a 1:1 stoichiometry. BrPAPS₂-Cu²⁺-PDADMAC allowed the selective recognition of GSH over other amino acids and the detection suffer little interference from them. Hence, BrPAPS₂-Cu²⁺-PDADMAC provides efficient colorimetric sensing of GSH with high selectivity and sensitivity in pure aqueous media.

The electrical conductivities of aqueous solutions of the azo dye methyl orange (sodium salt) were measured at 25.0 °C in the concentration range between 2.103 × 10^–4 and 9.255 × 10^–4 mol L⁻¹. Molar conductivity values fit the Debye–Hückel–Wager equation for a symmetric electrolyte. The estimated value of the molar conductivity of the sodium salt of methyl orange at infinite dilution is found to be 77.93 ± 0.38 S cm² mol⁻¹. The calculated ionic conductivity at infinite dilution of the anion of methyl orange is 27.82 S cm² mol⁻¹. Using the same methodology, a thermodynamic analysis of the association between methyl orange anion and α-cyclodextrin was conducted at 20.0, 25.0, 32.0, and 40.0 °C. The measured molar conductivities decreased as the mole ratio of α-cyclodextrin to methyl orange went below 3. The conductivity measurements were analysed using a model 1:1 stoichiometry at the four different temperatures. The values of the thermodynamic quantities ∆H° and ∆S° for the inclusion process were calculated by using Van’t Hoff plot, their values are − 27.35 kJ mol⁻¹ and − 9.70 J K⁻¹ mol⁻¹ respectively. For this case of the studied inclusion process this inclusion was disfavored through entropy change and favored through enthalpy change.

We have prepared two new heterotrihalides inside methyl-bambus[6]uril, [Br₂Cl]⁻@MeBU[6] and [BrICl]⁻@MeBU[6], both in solution and in the solid state. These heterotrihalides were used alongside with the first one our group has produced, [I₂Cl]⁻@MeBU[6], as halogenation agents in classical halogenation and iodine-based catalysts for organic reactions, with comparable yields to those obtained with pure dihalogens.

Calixarene derivatives exhibit excellent extractability and selectivity for metal ions based on their chelating and size-discriminating effects; however, their poor solubility in aliphatic hydrocarbons, which are used as solvents in industrial processes, hinders their practical use. In this study, the relationship between solubility of calix[4]arene acetic-acid derivatives in various organic solvents and Hansen solubility parameters of the solvents was investigated. The center coordinates of the Hansen solubility sphere of the p-tert-octylcalix[4]arene acetic-acid derivative (^tOct[4]CH₂COOH), as determined from its solubility in 50 different solvents, are δ_D = 17.24, δ_P = 4.73, δ_H = 4.45, which indicate that this extractant is less polar than p-tert-butylcalix[4]arene acetic-acid derivative. The solubilities of ^tOct[4]CH₂COOH in diethylene glycol dibutyl ether (DBC) and 2-nonanone (2-NON) were 92.6 mM and 91.1 mM, respectively. DBC and 2-NON are relatively preferable as solvents from the viewpoint of physical properties (low viscosity, relatively low water solubility, and high flash point). Extractability of Pb(II) using ^tOct[4]CH₂COOH dissolved in various solvents was compared. Extraction in DBC proceeded at much higher pH than that in other solvents. Extraction of various metals in 2-NON proceeded at higher pH than that in chloroform. The order of metal selectivity of ^tOct[4]CH₂COOH in 2-NON was similar to that in chloroform. The extraction reaction for Pb(II) using ^tOct[4]CH₂COOH was determined by slope analysis. These results suggest that 2-NON can be an alternative to chlorinated solvents for use of ^tOct[4]CH₂COOH as a metal extractant.

The synthesis of tree new macrocycles with two pyrazole–tetrazole subunits and a lateral arm is described. These macrocycles were characterized by NMR, FT-IR and UV–Vis spectroscopies as well as elemental analysis and mass spectrometry. The complexing properties of these compounds toward some heavy metal ions Pb²⁺, Co²⁺, Cd²⁺, Zn²⁺ and Cu²⁺ were investigated by liquid–liquid extraction. The obtained results show, that all macrocycles possess good ability to extract these heavy metal cations, except, the macrocycle M_III with an aromatic side chain which showed a weak potency. At the competitive conditions, all macrocycles presented some selectivity towards the extraction of Cd²⁺. In addition, the ability of these macrocycles to extract the cadium cation is affected by the pH of the solution.

A novel multi-hybrid hemicucurbituril with good solubility in organic solvent has been synthesized by combining derived glycoluril, ethyleneurea, and aromatic group in one macrocycle. This macrocycle has exhibited properties in photoresponse and derivatization, and showed obvious interaction with Fe³⁺ and Cu²⁺ by the fluorescence spectra study. The modified hemicucurbituril could be easily converted to another imidazolidine-2,4-dione-containing macrocycle.

Essential oils (EOs) and aromas have long been used in the perfume, cosmetic, pharmaceutical and food industries. Yet, aside their poor solubility and instability, their high volatility limits their application. Their encapsulation in cyclodextrins (CDs) or their solvation in deep eutectic solvents (DESs) are two efficient strategies to resolve such problems. Thus, the present study aims to investigate the retention ability of the combination of DESs and CDs towards a wide variety of EOs and aromas. Thus, the capacity of formulations combining choline chloride:urea (ChCl:U) DES, CDs and water to retain and decrease the volatility of twenty EOs and twenty-one aromas was examined. Also, the formation constants (K_f) of CD/aroma inclusion complexes in this new non-conventional medium were determined. Results showed that ChCl:U DES:water 70:30 wt% mixed with 10 wt% CD had an efficient ability to retain all the studied EOs and aromas. Also, the addition of CDs in this mixture was shown to be advantageous in improving the efficiency of the formulation even if lower complexation ability towards the aromas was observed compared to water. Altogether, the obtained results will encourage the use of DES:water:CD mixtures for the incorporation of EOs and aromas in different preparations.

Aminopterin (AMT) is a kind of universal antineoplastic drugs, but it has severe toxic and side effects, leaving it rarely used in clinic. Herein, we found that cucurbit[7]uril (CB[7]) and AMT can form stable inclusion complexes, and the formation of CB[7]-AMT 2:1 supramolecular inclusion complex was confirmed by UV-visible absorption spectra, fluorescence spectra, ¹H NMR, and molecular modeling calculations in aqueous solution. Binding stability constants (Ks) were determined by UV-visible and fluorescence spectra method, with 3.88 × 10¹⁰ L² mol^–2 and 5.24 × 10¹⁰ L² mol^–2, respectively. The binding energy was calculated to be 102.6 kcal mol^–1 for the CB[7]-AMT complex. And then, through a series of cell experiments of CCK8 assay, DAPI staining and hoechst33342/PI double staining, we fully proved that the CB[7]-AMT complex can reduce the toxicity of AMT to normal cells such as hepatocyte line LO2, and improve its anticancer effect on cancer cells overexpressing spermine, typically like human colon cancer cell line HCT116. It confirmed that the CB[7]-AMT complex had the effect of reducing toxicity and increasing efficiency. These results indicated that CB[7]-AMT inclusion complex might be a promising novel formulation of AMT for its clinical development.

Nowadays, due to the rapid development of the times, the study of green controlled release active packaging film has become an integral part of food packaging industry. In order to prepare eco-friendly food green packaging with sustainable release of active ingredients, this study used saturated aqueous solution method to prepare p-methoxybenzaldehyde/β-cyclodextrin inclusion complex, and analyzed the effects of three single factors, namely inclusion temperature, mixing time and inclusion ratio, on the entrapment efficiency and loading capacity. It is found that when the inclusion temperature was 50 °C, mixing time was 4 h and inclusion ratio was 10:1, the entrapment efficiency was 75.18%, the loading capacity could reach 7.52%. Meanwhile, the molecular docking method was used to study molecular interactions, indicating that p-methoxybenzaldehyde can form stable inclusion complexes with β-cyclodextrin. Polylactic acid (PLA) was then used as the base fluid to prepare a p-methoxybenzaldehyde releasable film, which was protected by β-cyclodextrin resulting in a significantly lower release rate than that of added p-methoxybenzaldehyde directly to the film. The inclusion complex was only physical mixing and did not react with PLA, and the inclusion of β-cyclodextrin allowed for effective control of the continuous release of p-methoxybenzaldehyde from the film.

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