Mild and Efficient Preparation of N-Heterocyclic Organic Molecules by Catalyst-free and Solvent-free Methods.

AIMS: The small organic molecular compounds with biological activity containing C-C and C-N or C-O bonding were efficiently prepared without catalyst and solvent in the hydrothermal synthesis reactor. OBJECTIVES: Our goal was to explore new applications for the more environmentally friendly and efficient synthesis of bis(indolyl)methyl, xanthene, quinazolinone, and N-heterocyclic derivatives in hydrothermal synthesis reactors under solvent-free and catalyst-free conditions. METHODS: A greener and more efficient method was successfully developed for the synthesis of bis(indolyl)methyl, heteroanthracene, quinazolinone, and N-heterocyclic derivatives using a hydrothermal synthesis reactor in a solvent- and catalyst-free manner. RESULTS: In a hydrothermal synthesis reactor, bis(indoyl)methyl, xanthene, quinazolinone, and N-heterocyclic derivatives were synthesized without catalysts and solvents. CONCLUSION: Overall, it is proved once again that the catalyst-free and solvent-free synthesis method has universal value and is a more ideal and environmentally friendly new method, especially the hydrothermal reactor for synthesis.

An anti-freeze fluorescent organogel with rapid shape-forming properties for constructing artificial light harvesting systems used in extremely cold environments.

Using polyvinyl alcohol (PVA) and perylene-3,9-dicarboxylic acid (PDA) as raw materials, a new anti-freeze (-50 °C) fluorescent organogel with rapid shape-forming (2 h) properties was synthesised based on a certain proportion of the binary solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). Then, an artificial light-harvesting system (ALHS) used in extremely cold environments was successfully constructed by mixing fluorescent dyes sulphorhodamine101 (SR101) and rhodamine 6G (R6G) into them as acceptors.

Acid protonation promoted different crystal phase structure silicon carbide-based carbon nitride composites to enhance the photocatalytic degradation of dye wastewater.

Acid-protonated crystalline silicon carbide-supported carbon nitride photocatalytic composites were successfully prepared by the impregnation-heat treatment method (P-g-C3N4/ß-SiC and P-g-C3N4/α-SiC). The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), UV-vis diffuse reflectance spectra (UV-vis-DRS) photoluminescence (PL), etc. The results of SEM showed that the P-g-C3N4/ß-SiC and P-g-C3N4/α-SiC materials were transformed from large-area lamellar structures to uniform and dispersed lamellar particles. The UV-vis-DRS and PL showed that the recombination probability of photogenerated electron-hole pairs of P-g-C3N4/ß-SiC and P-g-C3N4/α-SiC samples decreased and the band gap increased. The results of photocatalytic degradation of alizarin red S (ARS), acid fuchsin (AF), and basic fuchsin (BF) showed that the samples P-g-C3N4/ß-SiC and P-g-C3N4/α-SiC had excellent photocatalytic degradation performance. It is worth noting that the degradation performance of the sample P-g-C3N4/ß-SiC on the three dyes is better than that of P-g-C3N4/α-SiC. The electron spin resonance spectra (ESR) results showed that the ˙O2- and ˙OH produced by the two catalysts during the dye degradation process played a leading role in the degradation reaction. Fortunately, the catalyst maintains an excellent cycle life and can be reused more than seven times while degrading all three dyes.

Rapid Radiation Synthesis of a Flexible, Self-Healing, and Adhesive Ionogel with Environmental Tolerance for Multifunctional Strain Sensors.

Ionogels are increasingly used in flexible strain sensors, but it is still challenging to incorporate multifunctional properties such as flexibility, self-healing, adhesion, temperature resistance, and electrical conductivity. Herein, a facile and rapid one-step photoinitiated polymerization strategy is employed to prepare multifunctional ionogels by filling a hydrophobic and conductive ionic liquid into a flexible, hydrophobic fluoropolymer matrix. Thanks to the presence of abundant noncovalent interactions (hydrogen-bonding and ion-dipole interactions), the ionogels exhibit high transparency, excellent mechanical properties, self-healing ability, and adhesion. Moreover, rich C-F bonds in the fluoropolymer matrix can eliminate the interference of water molecules, resulting in excellent environmental tolerance such as high and low temperature resistance, waterproofness, and anticorrosion. Furthermore, the ionogel-based wearable strain sensor can sensitively detect and differentiate human movements and subtle muscle movements and serve as a Morse code signal transmitter for information transmission. The presented work provides an effective method to develop versatile flexible conductive ionogels for wearable devices and ionotronics.

Shape-controlled hollow Cu2O@CuS nanocubes with enhanced photocatalytic activities towards degradation of tetracycline.

In view of recent advances in photodegradation of antibiotics, low cost and stable photocatalyst remain rare. In this article, shape-controlled Cu2O@CuS nanocubes with the larger specific surface area were successfully prepared via a simple template-engaged strategy. Cu2O nanocubes were synthesized through a reduction method as original templates, the core-shelled Cu2O@CuS nanocubes were formed by sulphuration with Na2S as sulphur source, and the Cu2O core can be incompletely removed by Na2S2O3 to generate the Cu2O@CuS nanoboxes. Herein, hierarchical nanoboxes with two-layered Cu2O@CuS were used as photocatalyst materials for photocatalytic degradation of tetracycline (TC). The obtained nanocubes manifested high specific surface area (39.65 m2 g-1) and large pore volume (12.3 cm3 g-1). The degradation performance for TC was investigated in detail, including the effect of parameters such as photocatalyst, pH and catalyst dosage. The results indicated that degradation efficiencies were higher than 90% under visible light. Moreover, the degradation efficiency was 71% after six times.

A κ-Carrageenan-Containing Organohydrogel with Adjustable Transmittance for an Antifreezing, Nondrying, and Solvent-Resistant Strain Sensor.

Gel polymers are widely used in different fields due to their unique properties, especially in flexible electronic devices. However, developing multienvironmentally-tolerant (antifreezing, antidrying, and solvent-resistant) gel polymer-based soft electronics is still a significant challenge. Herein, a binary solvent system-based versatile organohydrogel is designed and successfully prepared, which exhibits superior stretchability, favorable self-adhesive properties, prominent temperature tolerance, and excellent solvent-resistant capabilities. Furthermore, the as-assembled organohydrogel-based sensor demonstrates a satisfied sensitivity (GF = 1.8), wide strain range (5-500%), and outstanding human motion detection. Meanwhile, the obtained organohydrogel can also serve as an all-weather sensor for achieving precise and reliable mechanical sensing in a wide temperature range from -50 to 50 °C and diverse liquid media consisting of water, toluene, and carbon tetrachloride. Interestingly, the organohydrogel displays a repeatable transmittance change behavior in water and dimethyl sulfoxide, based on this feature, which could realize the functional applications for recording and erasing information. It is envisioned that these superior performances render the as-prepared organohydrogel suitable to develop future advanced soft electronics with multienvironmental tolerance.

Efficient artificial light-harvesting systems based on aggregation-induced emission in supramolecular gels.

Based on a new designed acyl hydrazone gelator (G2), we developed a supramolecular organogel in glycol with two different hydrophobic fluorescent dyes, namely rhodamine B (RhB) and acridine red, as acceptors. Both the G2@gel-RhB and G2@gel-acridine red systems showed high levels of energy-transfer efficiency and high fluorescence quantum yields.

A new strategy for constructing artificial light-harvesting systems: supramolecular self-assembly gels with AIE properties.

An artificial light-harvesting system (ALHS) has been designed and constructed based on supramolecular organogels made of a simple hydrazide-functionalized benzimidazole derivative (HB), as well as the fluorescent dye rhodamine B (RhB). RhB acted as a good acceptor to realize the energy-transfer process with good efficiency based on a HB/RhB assembly, which showed considerable fluorescence resonance energy transfer (FRET) efficiency of 53% for the energy transfer process. Remarkably, the obtained system showed superior color conversion abilities, converting blue light into orange light. By properly tuning the donor to acceptor ratio, bright orange light emission was achieved with a high fluorescence quantum yield of 35.5%. This system exhibited promise for applications relating to visible-light photo-transformation.

Intelligent writable material based on a supramolecular self-assembly gel.

A simple dual acylhydrazone-functionalized gelator (G1) has been designed and synthesized, and it was found to form a supramolecular organogel (G1-gel) in a mixed solvent of DMF-H2O. The gelator solution shows brilliant blue light upon mixing with Mg2+; this blue light can be erased by saliva or CO32-. Owing to this characteristic, a smart erasable writable material was prepared.

Preparation and properties of organic-inorganic composite superabsorbent based on xanthan gum and loess.

A new, low-cost, and eco-friendly organic-inorganic composite superabsorbent was successfully synthesized in aqueous solution by polymerization xanthan gum (XG), neutralized acrylic acid (AA) and loess using ammonium persulfate (APS) as initiator and N,N-methylenebisacrylamide (MBA) as crosslinker. Structure and morphological characterizations of the composite superabsorbent were investigated by Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The loess content, pH values, surfactants, salts and temperature which could affect the swelling and water-retention capabilities of the composite superabsorbent were investigated. The composite superabsorbent exhibits excellent water absorbency (610 g/g in distilled water), pH-stability (pH 5-10), and higher swelling capacity in anionic surfactant solution; on the other hand, the composite superabsorbent can be used for removing multivalent metal ions.