Journal of Inclusion Phenomena and Macrocyclic Chemistry最新文献

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.

Metformin hydrochloride (MET) (N,N-dimethylbiguanide) is an antidiabetic drug and widely used for treating worldwide disease, Type 2 diabetes. MET shows significant benefits for human health such as reducing high blood sugar and cholesterol/triglyceride levels, treating for polycystic ovary syndrome and having anticancer and antiaging effects. In this study, a facile colorimetric determination of metformin in drug preparations was carried out by environmentally friendly gamma-cyclodextrin (γ-CD) stabilized silver nanoparticles (CD-AgNPs). Gamma-cyclodextrin was used for the formation of AgNPs as both the metal salt − reducing and nanoparticle − stabilizing agent. As a visual optical probe, well-dispersed spherical yellow-colored CD-AgNPs (at an average particle size of 10 ± 2 nm) showing maximal surface plasmon resonance absorption at 405 nm was synthesized by one-step method. In the presence of metformin, dispersed AgNPs get aggregated, and a controlled destabilization of CD-AgNPs and core-centered growth of Ag(0) atoms (20 ± 2 nm) were observed a result of host-guest interaction between CD-AgNPs and metformin. Non-covalent hydrogen bonding between the hydroxyl groups of CD-AgNPs (in the outer cavity) and the guanidine groups of MET enables the CDs to form a host-guest inclusion complexation followed by aggregation leading to color change from yellow to orange and an increase of the absorbance at 550 nm. Inclusion complex formation was characterized by using FTIR, UV-Vis spectroscopy, DSC and STEM techniques. Under optimized conditions, the absorbance ratio at A_{550 nm}/A_{405 nm} was linearly correlated to the concentration of metformin in the range of 0.2–1.25 µM. The proposed assay showed high sensitivity with 42 nM detection limit. The method was selective toward possible interferents (potassium, carbonate, sulfate, chloride and sodium ions, urea, glucose) and also successfully applied to conventional drug samples including MET. The results obtained by proposed, reference and HPLC assays were analyzed statistically using the two-way ANOVA test to demonstrate their agreement with each other at 95% confidence level (P = 0.05, F_exp = 0.068, F_crit(table) = 6.943, F_exp < F_crit(table)). MET contents (mg) of drug samples in tablet form were determined with high accuracy (REC% 97.3-100.7) and reproducibility (RSD% 1.49–2.78). It is noteworthy that the developed CD-AgNP − based colorimetric method seems to be of higher or comparable sensitivity compared to other nanoparticle − based optical assays.

In the field of wearable electronics, MXenes have emerged as promising two-dimensional (2D) materials, exhibiting exceptional properties such as metallic conductivity, water dispersibility, thermal stability, mechanical stability, and high optical transmittance. In this study, we present a unique flexible transparent conductive electrode (FTCE) composed of MXene, Ag nanowire (AgNW), ultraviolet resin (UV-resin), and polycarbonate (PC). Our fabrication process involves a roll-to-roll process and entirely solution-based methods including UV-resin dispensing, AgNW solution coating, and FTCE dipping in an MXene solution, providing a cost-effective manufacturing approach. Notably, compared to the pure AgNW-based FTCE, the proposed FTCE incorporating an MXene concentration of 5 mg/mL showed a significant enhancement of 40% in electrical conductivity, while the FTCE with a concentration of 2 mg/mL exhibited an improved figure of merit. Furthermore, we successfully demonstrate an embedded system integrating the FTCE-based capacitive touch and proximity sensor. These achievements in optoelectronic performance signify a tremendous potential for the development of high-performance flexible devices.

This short note shows that the Scott test, which is widely used for the detection of cocaine by authorities, produces false-positives for the entire series of cucurbit[n]uril-type uril macrocycles and also for hemi-cucurbit[n]uril. For analogous macrocycles such as bambus[6]uril and biotin[6]uril this does not happen. This is a wake-up call to the scientific community and international authorities.