Journal of Inclusion Phenomena and Macrocyclic Chemistry最新文献

Physico-chemical and structural characteristics have been studied of ionic clathrate hydrates of cross-linked (n = 1%) tetraisoamylammonium (TiAA) polyacrylates with different extent of substitution of proton-ions of the carboxylic groups for TiAA cations (x = 77%, 60%, 40%) in the polyacrylate. Powder X-ray diffraction studies have been carried out. All hydrates are isostructural to the earlier studied clathrate hydrate of cross-linked TiAA polyacrylate with x = 100%. The hexagonal structure with the space group P6/mmm and slightly different unit cell parameters (a ~ 12.24 Å, c ~ 12.70 Å) is related to the idealized Hexagonal Structure I of clathrate hydrates. Compositions, phase transition temperatures and decomposition enthalpies of the hydrates have been determined using differential thermal analysis and differential scanning calorimetry. The stability of the hydrates structure decreases with lessening of the content of TiAA cations in the polymeric molecule. The hydrates decomposition temperatures go down from + 14.6 to + 9.8 °C (for x = 100–40%) and the decomposition enthalpies—from 189.1 kJ/mol of hydrate to 84.0 kJ/mol of hydrate (for the same interval of x). The comparison has been made of physico-chemical characteristics of the ionic clathrate hydrates of cross-linked TiAA polyacrylates with those of the hydrates of tetrabutylammonium (TBA) polyacrylates and also of the ionic clathrate hydrates of TBA salts with monomeric anions.

A series of mono-functionalized pillar[5]arene Schiff bases were successfully synthesized by amidation reaction of pillar[5]arene mono-O-butyrate with various diaminoalkanes and sequential condensation reaction of monoaminoalkyl-functionalized pillar[5]arenes with substituted salicylaldehydes. ¹H NMR and 2D NOESY spectra clearly showed that all monoaminoalkyl-functionalized pillar[5]arenes could form pseudo[1]rotaxanes by self-sorting of aminoalkyl chain into the cavity of pillar[5]arene, while pillars[5]arene Schiff bases with longer than butylene chain (n ≥ 4) could form stable [1]rotaxane. The fluorescence spectrophotometry indicated that pillar[5]arene Schiff bases coordinated with Zn²⁺ ion to form interesting complexes with 2:1 coordination ratio and with significant enhance of the fluorescence intensity.

As one of carbon-based nanomaterials, single-walled carbon nanotubes (SWCNTs) are widely regarded as potentially potent drug delivery carriers on account of their prominent properties. Nevertheless, their biomedical application, particularly in the drug delivery field has been seriously restricted by some inherent defects. In this study, SWCNTs materials were functionalized by covalent and non-covalent approaches, respectively. In short, the pristine SWCNTs were first purified with strong oxidizing acids (H₂SO₄/HNO₃), and the resulting carboxylated ones (CNTs) were attached sequentially by different modification agents, including polyethylene glycol (PEG), polyethyleneimine (PEI), folic acid (FA) and chitosan (CS). Various nanocarriers were then systematically characterized and comparatively evaluated. The results illustrated that all CNTs samples could act as drug delivery carriers since they had high drug loading efficiency, good biocompatibility and responsive drug release. In comparison with other CNTs, multi-functionalized ones (CNTs-PPFC) exhibited more excellent performance, such as rapid drug release at low pH condition, higher cell internalization efficiency, and enhanced antitumor activity toward MCF-7 cells. These advantages should be attributed to their better dispersion state and comparably higher affinity with tumor cells, which favor the more efficient selective cellular uptake and subsequent drug accumulation. Moreover, further pharmacological mechanism analysis also revealed that CNTs-PPFC/DOX could induce the apoptosis of MCF-7 cells most effectively, by triggering ROS overproduction and affecting cell cycle distribution. In conclusion, the multi-functionalized CNTs-PPFC can be utilized as promising nanocarriers, and the findings will contribute to the rational design of novel delivery vehicles for anticancer drugs.

Ketoprofen is a nonsteroidal anti-inflammatory drug used as mohrus tape which causes unwanted photosensitivity due to UV irradiation. In addition, photodegradation of ketoprofen induces its decarboxylation. Here, we aim to determine the effect of cyclodextrin on the photolysis of ketoprofen. Separation technique using HPLC confirmed that UV irradiation of ketoprofen produced multiple products. A unique reaction proceeded in the presence of β-cyclodextrin. Furthermore, characterization by UV spectroscopy was performed, and the obtained spectra were analyzed using singular value decomposition. By analyzing the trajectory of the singular vector space, we were able to reflect the difference in the reaction pathway of ketoprofen with and without cyclodextrin. This study uses a singular value decomposition analysis, which is useful as a novel approach for solutions of radical reactions and a promising technique for analysis of radical reactions in the future.

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Nitropyridine substituted double-armed benzo 15-crown-5 compounds (1–4) were synthesized by the reactions of 4′,5′-bis(bromomethyl)benzo-15-crown-5 with hydroxypyridine derivatives. Na⁺ and K⁺ complexes (1a–4a, 1b–4b) of crown ether compounds (1–4) were prepared with sodium picrate and potassium picrate, respectively. Transition metal complexes (1c–4c) of the synthesized ligands (1–4) were prepared from Ag⁺ cation. In addition, nitro compounds (1, 2 and 4) were reduced by using Pd/C and hydrazine hydrate and new amine compounds (5, 6 and 8) were obtained. The structures of new double-armed crown ether compounds (2–4), their metal complexes (1a–4a, 1b–4b, 2c–4c) and amine compounds (5, 6 and 8) were elucidated by FTIR, HRMS, ¹H–NMR, ¹³C–NMR spectroscopic methods. The thermal behaviors of these nitro group containing ligands (1–4) were compared with the resulting silver complexes (1c–4c) and amine compounds (5, 6 and 8). All synthesized compounds were examined for antibacterial activity against pathogenic strains Listeria monocytogenes, Salmonella typhi H, Bacillus cereus, Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Escherichia coli, Klebsiella pneumonia, Proteus vulgaris, Serratia marcescens, Shigella dysenteria and antifungal activity against Candida albicans.

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Acyclic cucurbit[n]urils are a novel type of cucurbituril derivatives, consisting of a central glycoluril tetramer skeleton, two substituted terminal aromatic rings, and four linkers bearing solubilizing groups. Due to flexible conformation and facile functionalization, acyclic cucurbit[n]urils are tailored to exhibit high binding affinity and selectivity toward a variety of guests. In this review, we focus on the relationship between structure and property of acyclic cucurbit[n]urils. The recent development of acyclic cucurbit[n]urils has paved the way for practical applications in pharmaceutical and biochemical areas.

The nano-porous crystals of γ-cyclodextrin MOF (CDMOF) were synthesized and encapsulated with benzaldehyde. The host–guest interactions between CDMOF and benzaldehyde were analyzed using fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and molecular docking calculations. We observed that around 13% benzaldehyde was adsorbed by the CDMOF crystals, which was supported by TGA, FTIR, DSC and XRD. The preferred inclusion geometry was identified, and the strength of these interactions was recorded. A polar carbonyl group was identified as a docking site which leads to stabilization and complex formation with glucopyranose unit of CDMOF. It was observed that the binding energy for the complex is—4.04 kcal mol⁻¹, which indicates that complex formation is thermodynamically favorable.

The combination of the electron donor and acceptor into a donor–acceptor system can transform the intermolecular charge transfer (CT) property into the intramolecular CT property, which is of great significance when exploring and expanding the application potential of conductive molecules. This work creatively incorporates tetracyanoquinodimethane (TCNQ, acceptor) and tetrathiafulvalene (TTF, donor) alternately into macrocyclic molecule, resulting in cyclopolymer of TCNQ-TTF (named C[n]QF, n = 4 − 7). The structures of C[n]QF are optimized by using density functional theory (DFT) at the M062X/6-311 g(d) level. DFT calculation results show that C[n]QFs have excellent intramolecular CT capability and multi-redox activity. Their absorption spectra are in the visible light range leading to good light responding properties. The double-walled assembly and host–guest inclusion performance of C[n]QF indicate their remarkable ability as building blocks for supramolecular systems. Based on DFT calculations, C[n]QF are expected to have potential applications in organic photoelectric, electrochemical sensing, and supramolecular materials.

Indocyanine green (ICG) angiography is of great importance for ophthalmic diagnostic applications and is mainly used to check for choroidal vascular diseases. However, ICG fluorescence imaging probes aggregate in water because they have sulfonyl groups and can form dimers and oligomers. This effect thus reduces the fluorescence of the probes. Therefore, we have established a simple and effective way to prepare β-cyclodextrinmodified ICG (ICG–β-CD) via the host–guest assembly process. In contrast to ICG, ICG–β-CD avoided solution aggregation. Moreover, it exhibited improved absorption intensity. When used as an angiographic contrast agent for ophthalmic choroid examination and diagnosis in SD rats, the fluorescence imaging effect of ICG–β-CD on retinal and choroidal vessels was better than that of ICG on choroidal vessels. Therefore, ICG–β-CD is expected to achieve a "two birds with one stone" effect.

Spectroscopic techniques have been used to improve the understanding of the interactions between hydroxyethyl starch (HES) 200/0.5 and human serum albumin (HSA) in a simulated physiological fluid of pH 7.4. It has been revealed that static fluorescence quenching occurred when HSA interacted with HES 200/0.5. The negative value of ΔH° (− 2.39 × 10⁴ J·mol⁻¹) and positive value of ΔS° (30.1 J·mol⁻¹·K⁻¹) suggested electrostatic interaction was the dominating force of the binding reaction between HES 200/0.5 to HSA, and the binding process was proved as a spontaneous one with negative ΔG° values (− 3.34 × 10⁵ J·mol⁻¹ at body temperature). The distance between HSA and HES 200/0.5 (r = 2.11 nm) proved efficient energy transfer from Trp to the drug. Moreover, the binding site of HES 200/0.5 to HSA was confirmed by site marker competitive experiments as Sudlow’s site I. Finally, it was observed that the conformation of HSA was changed with a loss of α-helical but acquisition of β contents, where a more stabilized secondary structure was formed.