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Hematoxylin has a V-shaped chiral geometry, but its potential in chiroptical self-assembled materials is underdeveloped. Herein, three novel V-shaped chiral hematoxylin derivatives were synthesized, and they showed extended skeletons as well as photophysical and chiroptical behaviors. Moreover, their host–guest interactions with C60 were investigated. Our findings could aid in the design and synthesis of novel chiral host molecules from natural products. [ABSTRACT FROM AUTHOR]

Natural amino acids are the most important building blocks in supramolecular chemistry which possess the best biocompatibility in nature. To the best of our knowledge, although hydrogels based on amino acid derivatives have already been studied widely, there is still no report about natural amino acids hydrogels constructed by metal ions induction method. Herein, the self‐assembly behaviors of twelve natural amino acids with eight metal ions were studied systematically. It is surprising that only sodium L‐Phenylalanine can self‐assemble into hydrogel with ZnCl2. Various methods were used to investigate the formation mechanism of hydrogel. The formation of hydrogel is triggered mainly via π‐π stacking and metal‐ligand interactions. Moreover, this green L‐Phenylalanine hydrogel displays acid responsiveness and relatively stability under high temperature, which has great potential applications in many fields. [ABSTRACT FROM AUTHOR]

In the 5G ultra-dense wireless heterogeneous network system, it is a crucial issue to implement an effective network selection strategy to satisfy the demands of massive edge users and novel 5G services. In this paper, we model the network selection problem of edge users requesting different services as a bipartite graph, and propose a network selection algorithm based on weighted bipartite graph matching for 5G ultra-dense heterogeneous networks, named BGMNS. The proposed algorithm combines Analytic Hierarchy Process (AHP) and Grey Relation Analysis (GRA) to analyze the preferences of multiple services for different network attributes and obtain the Quality of Experience (QoE) of different edge users for each network. Moreover, in order to realize the fair allocation of network resources, we comprehensively consider the importance of the requested services and the obtained QoE by edge users to construct system fairness index. The BGMNS algorithm can optimize the overall QoE of users under the premise of ensuring the system fairness. Simulation results show that compared to the existing network selection algorithms, the proposed BGMNS algorithm can not only provide stable access to users when network status fluctuates randomly, but also effectively reduce user blocking probability as well as total packet loss rate, and significantly improve user average energy efficiency. [ABSTRACT FROM AUTHOR]

The rate constants of two redox reactions Fe (CN)64−+S2O82− and Fe (phen)32++S2O82− in the critical solution of 2‐butoxyethanol and water have been measured by using the UV spectrophotometry at the initial reaction stage. It was found that the rate constants at various temperatures for two reactions were well described by the Arrhenius equation in the noncritical region. The critical slowing down effect was detected in the critical region. The critical slowing down exponents were determined to be 0.044 ± 0.004 and 0.046 ± 0.005 for reactions Fe (CN)64−+S2O82− and Fe (phen)32++S2O82−, respectively. The values of the critical slowing down exponents showed that only dynamic critical slowing down effect, and no thermodynamic singularity could be observed for the two reactions. [ABSTRACT FROM AUTHOR]

Gel formation by an N-fluorenyl-9-methoxycarbonyl (Fmoc)-based molecule was investigated and the chirality amplification observed during the self-assembly process could be switched on and off by controlling the solvent environment. The molecules could form gel in mixed solvents of water and dimethyl sulfoxide (DMSO) at either a high water fraction to afford flat nanofibers or a low water fraction to generate nanofibers with supramolecular chirality. At a moderate fraction of water, the molecules self-assemble into a precipitate composed of nanosheets. Furthermore, the gels showed different mechanical properties and thermal stabilities. Mechanism studies showed that π–π stacking interactions between the aromatic Fmoc groups and hydrogen bondings between the amide groups played important roles in the self-assembly process of the different gels. This study strives to shed light on the tuning of chiral gels with various nanostructures via controlled self-assembly, which might have potential use in smart materials. [ABSTRACT FROM AUTHOR]

Self-assembly of N-fluorenyl-9-methoxycarbonyl glutamic acid (Fmoc-Glu) in water generates metastable single-wall nanotubes. These nanotubes entangle and bundle together to form unstable gels that shrink with time and finally result in lamellar crystalline precipitates. Melamine (Mm) was employed as a supramolecular modifier and stabilizer to improve the stability of the nanotubes. Mm interacts with the carboxyl-rich surfaces of the nanotubes via H-bonds and static electronic forces to diminish the high affinity of individual nanotubes and facilitate Fmoc-Glu supergelation (critical gelation concentration <0.1 wt %). Although the basic process of nanotube formation is not disturbed, Mm inverts the supramolecular helicity of nanotubes from P to M. [ABSTRACT FROM AUTHOR]

Curcumin is a safe and nontoxic natural potential antitumor drug. However, its extremely low aqueous solubility severely limits its clinical application. We designed a supramolecular curcumin vesicle based on different curcumin-cyclodextrin amphiphiles, which could greatly enhance the aqueous solubility of curcumin up to 7000-fold. The vesicles can exist for about one month in aqueous solution at around 20 °C, showing a certain colloidal stability. The curcumin-β-cyclodextrin vesicles were identified by transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), and dynamic light scattering (DLS). X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV–vis spectrum and 1 H NMR were further employed to study the formation mechanism of the vesicles. Curcumin vesicles were also prepared when different host molecules were employed as the hydrophilic heads of the supramolecular amphiphiles. Finally, curcumin could be controllably released with the disruption of the vesicles when the external stimuli, including competitive guest molecules, enzymes and copper ions were added into the vesicles system. [ABSTRACT FROM AUTHOR]

Highlights: [•] The supramolecular vesicles constructed by cyclodextrin–ftorafur supramolecular amphiphiles are reported. [•] The mechanism of the vesicles formation was studied by various methods. [•] The effect of copper ions on the vesicles was discussed. [•] The antitumor effects of the ftorafur-loaded vesicles on human colon carcinoma cell lines HT-29 were studied in detail. [Copyright &y& Elsevier]

Through a good/poor solvent strategy, native folic acid (FA) which behaves as a super-gelator in DMSO–water system can be successfully employed to construct supramolecular gels. The system exhibited morphological evolution with the increase of FA concentration; various phases such as vesicles, fiber/vesicles, fiber/nanoparticles, nanoparticles were probed. In the self-assembly process, l-glutamic acid moiety induced the formation of helical 1-dimensional (1-D) fibers which further self-assembled into a gel. Stimuli like heat, stress, pH and light which affect the molecular structure of FA or solubility in the mixed solvents had a pronounced influence on the properties of the gels, such as mechanical properties or bulk phases. A time-dependent oscillatory stress scan indicated that the supramolecular gel had a self-healing property. Without tedious modification routes and addition of alkali metal ions, native FA which served as an efficient building block and super-gelator to build up multi-responsive and self-recovery material was investigated for the first time. [ABSTRACT FROM AUTHOR]

A new method was developed to construct a special amido bond in the presence ofβ-cyclodextrin. This process is similar to peptide synthesis in organisms. NMR experiments were performed to investigate the possible mechanism. This work has potential application in biomimetic peptide synthesis. [Supplementary materials are available for this article. Go to the publisher's online edition ofSynthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] [ABSTRACT FROM AUTHOR]

Anisotropic and well-defined β-cyclodextrin (β-CD) and sodium laurate (SL) gel fibers, with tetragonal and lamellar packing modes respectively, were combined to generate orthogonal and switchable assemblies for the first time. Through controlling the inclusion–exclusion processes between β-CD and SL by changing external stimuli, β-CD gel fibers, SL gel fibers and their coexistence states can be easily tailored. Different assembled states exhibited versatile morphologies and microstructures, which were detected by microscopy and X-ray scattering measurements. Furthermore, controllable assemblies provide facile ways to control the mechanical properties of the hybrid gels. The orthogonal self-assembly with self-sorting properties would enable this system to attract interest in material science. [ABSTRACT FROM AUTHOR]

Abstract: Vesicles constructed by supramolecular amphiphiles are considered as more promising stimuli-responsive vehicles for carrying and delivering targeted molecules. In this research, novel supramolecular amphiphiles are directly assembled from UR-144, a general neuropathic drug, and a class of mono-diaminoalkane substituted β-cyclodextrins. In the aqueous solution, the supramolecular amphiphiles can assemble into vesicular particles, which were characterized in detail by transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning electron microscopy (SEM) and dynamic light scattering (DLS). The mechanism was also suggested based on the NMR, Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) experimental results. The vesicular particles tend to be damaged upon the addition of Cu2+ and meanwhile release UR-144. [Copyright &y& Elsevier]

An efficient and practical C–N bond formation methodology for the synthesis of N‐alkylated (benzo)thiazoles was developed, via the copper‐catalyzed one‐pot two‐step reactions of 2‐amino(benzo)thiazoles and aldehydes (ketones) with tosylhydrazide. This cross‐coupling reaction proceeded smoothly and tolerated a broad range of functional groups (46 examples). A variety of functionalized N‐alkylated (benzo)thiazoles were obtained in moderate to high yields. Notably, gram‐scale synthesis of fanetizole (anti‐inflammatory drug) was also realized through this protocol. [ABSTRACT FROM AUTHOR]

The donor-acceptor distance is a critical factor for the occurrence of chemiluminescent resonance energy transfer (CRET). We herein evaluate the donor-acceptor distance and transfer efficiency of CRET immunoassays of a series of donors which contain different sized antibody fragments, intact monoclonal antibody (IgG), antigen binding fragment (Fab), and single chain fragment antibody (scFv). Core/multishell quantum dots were used as the acceptor in three CRET systems. IgG is the maximum antibody fragment, leading to the longest donor-acceptor distance and the lowest transfer efficiency. Donors with Fab and scFv show significantly decreased distance and increased transfer efficiency. These results suggest an inverse correlation between donor size and transfer efficiency and can be used to provide guidance for the construction of controllable CRET. By combining the controllable CRET with immunoassay, we further develop a tunable sulfamethazine analytical system. Three different sized donors based CRET immunoassay show a markedly different sensitivity and dynamic range. Such adjustable detection provides greater flexibility for contaminant detection in different foodstuffs with different residue limits. This work not only illustrates the effect of donor-acceptor distance on regulating the energy transfer efficiency of CRET system, but also provides a guideline for the construction of a tunable immunoassay. Image 1 • We developed a CRET-based immunoassay with tunable sensitivity and dynamic range. • Controllable CRET was driven by antibody engineering. • Three antibody fragments with different sizes were used as donors in CRET system. • This work provides a guideline for the construction of a tunable immunoassay. [ABSTRACT FROM AUTHOR]